PORT-AU-PRINCE, Haiti (AP) -- Prayers of thanksgiving and cries for help rose from Haiti's huddled homeless Sunday, the sixth day of an epic humanitarian crisis that was straining the world's ability to respond and igniting flare-ups of violence amid the rubble of Port-au-Prince.
Haitian police struggled to scatter hundreds of stone-throwing looters in the city's Vieux Marche, or Old Market. Elsewhere downtown, amid the smoke from bonfires burning uncollected bodies, gunfire rang out and bands of machete-wielding young men roamed the streets, faces hidden by bandanas.
A leading aid group complained of skewed priorities and a supply bottleneck at the U.S.-controlled airport. The general in charge said the U.S. military was "working aggressively" to speed up deliveries.
Beside the ruins of the Port-Au-Prince cathedral, where the sun streamed through the shattered stained glass, the priest told his flock at their first Sunday Mass since Tuesday's earthquake, "We are in the hands of God now."
The former president of the United States, Bill Clinton, takes bottles of water out of his plane, January 18, 2010 at the international airport of Port-au-Prince. AFP PHOTO OLIVIER LABAN-MATTEI (Photo credit should read Olivier Laban mattei/AFP/Getty Images)
An injured woman waits for medical attention outside a hospital in Port-au-Prince on January 18, 2010. Aid agencies said a huge international relief operation nearly a week after Haiti's devastating earthquake was gaining pace on Monday, but one warned that survivors were growing increasingly desperate. AFP PHOTO/Luis Acosta (Photo credit should read LUIS ACOSTA/AFP/Getty Image
People take goods from collapsed stores in the market area in Port-au-Prince, Monday, Jan. 18, 2010. Violence and looting broke up in Port-au-Prince as earthquake survivors scavenged for anything they could find in the ruins. (AP Photo/Gerald Herbert)
People take goods from a quake-collapsed store in Port-au-Prince, Monday, Jan. 18, 2010. (AP Photo/Ricardo Arduengo)
People take packets of spaghetti from a burning warehouse in Port-au-Prince, Monday, Jan. 18, 2010. Looting spread to more parts of the city as people broke into stores and buildings damaged during last week's earthquake to take whatever they can find. (AP Photo/Gregory Bull)
Bill Clinton, former President and U.N. special envoy for Haiti, right, greets a woman during a visit to the General Hospital in Port-au-Prince, Monday, Jan. 18, 2010. Clinton promised that his foundation would provide medicine and a generator to the capital's General Hospital in order to doctors there can work through the night. (AP Photo/Lynne Sladky)
A boy injured during last week's earthquake is treated at the Israeli Field Hospital in Port-au-Prince, Monday, Jan. 18, 2010. (AP Photo/Ricardo Arduengo)
Rescue workers from Russia, Nicaragua, Peru and Israel team up to pull a woman from the rubble of a collapsed building in Port-au-Prince, Monday, Jan. 18, 2010. The woman was one of two survivors pulled from the building just minutes apart from each other. (AP Photo/Julie Jacobson)
Maxi Phalone sings praises to God after her sister was pulled alive from the rubble of a collapsed building in Port-au-Prince, Monday, Jan. 18, 2010. Phalone's sister was one of two earthquake survivors freed from the rubble by rescue workers from Russia, Nicaragua, Peru and Israel. (AP Photo/Julie Jacobson)
A woman walks past a fire during widespread looting in Port-au-Prince, Sunday, Jan. 17, 2010. Five days after Haiti was rocked by a major earthquake, hundreds of residents of the capital looted damaged downtown stores. (AP Photo/Gregory Bull)
Sgt. Allen Robinson from the 2nd Brigade, 82nd Airborne Division, looks at a collapsed building as he sits in the back of a vehicle carrying disaster relief supplies in Port-au-Prince, Haiti, Sunday, Jan. 17, 2010. Relief groups and officials are focused on moving aid flowing into Haiti to survivors of the powerful earthquake that hit the country on Tuesday. (AP Photo/Jae C. Hong)
Haitians walk with their hands in the air past Haitian police who are trying to keep order at a market area in the aftermath of the powerful earthquake in Port-au-Prince, Sunday, Jan. 17, 2010. (AP Photo/Gerald Herbert)
A man, center, gestures after being detained by Haitian police for looting in Port-au-Prince, Sunday, Jan. 17, 2010. Five days after Haiti was rocked by a major earthquake, hundreds of residents of the capital looted downtown damaged stores. (AP Photo/Gregory Bull)
A couple runs past a burning body in Port-au-Prince, Sunday, Jan. 17, 2010. U.N. peacekeepers patrolling the capital said popular anger is rising and warned authorities and aid organizations to increase security to guard against looting after Tuesday's earthquake. (AP Photo/Gerald Herbert)
A man walks past a sign set up in front of a destroyed house in Port au Prince on January 17, 2010, five days after an earthquake majoring 7.0 only open-ended Richter scale hit the Haitian capital. Aid is pouring into the earthquake-stricken Caribbean nation of Haiti, even as officials try to estimate the scale of the devastation in a complex and evolving human tragedy. AFP PHOTO / NICHOLAS KAMM (Photo credit should read NICHOLAS KAMM/AFP/Getty Images)
Looters run during a police assault, January 17, 2010 near the Hypolite Market in Port-au-Prince. Aid is pouring into the earthquake-stricken Caribbean nation of Haiti, even as officials try to estimate the scale of the devastation in a complex and evolving human tragedy. AFP PHOTO /OLIVIER LABAN-MATTEI (Photo credit should read Olivier Laban mattei/AFP/Getty Images)
Men carry water in Port-au-Prince, Sunday, Jan. 17, 2010. Relief groups and officials are focused on moving the aid flowing into Haiti to survivors of the powerful earthquake that hit the country on Tuesday. (AP Photo/Gregory Bull)
A woman receives medical attention after her leg was amputated due to injures received during Tuesday's earthquake in Port-au-Prince, Sunday, Jan. 17, 2010. (AP Photo/Ariana Cubillos)
People walk amidst damaged buildings and fires in the market area in Port-au-Prince, Haiti, Sunday, Jan. 17, 2010. U.N. peacekeepers patrolling the capital said popular anger is rising and warned authorities and aid organizations to increase security to guard against looting after Tuesday's earthquake. (AP Photo/Gerald Herbert)
U.N. Secretary-General Ban Ki-moon , center, visits the collapsed UN headquarters during his visit to Port-au-Prince, Sunday, Jan. 17, 2010. (AP Photo/Francois Mori)
Haiti's President Rene Preval, left, looks at the wounds of an earthquake survivor in Port-au-Prince, Sunday, Jan. 17, 2010. (AP Photo/Ramon Espinosa)
But anger mounted hourly that other helping hands were slow in getting food and water to millions in need.
"The government is a joke. The U.N. is a joke," Jacqueline Thermiti, 71, said as she lay in the dust with dozens of dying elderly outside their destroyed nursing home. "We're a kilometer (half a mile) from the airport and we're going to die of hunger."
Water was delivered to more people around the capital, where an estimated 300,000 displaced were living outdoors. But food and medicine were still scarce.
The crippled city choked on the stench of death and shook with yet another aftershock Sunday. On the streets, people were still dying, people were on their knees praying for help, pregnant women were giving birth on the pavement, and the injured were showing up in wheelbarrows and on people's backs at hurriedly erected field hospitals. Authorities warned that looting and violence could spread.
At the Vieux Marche, police tried to disperse looters by driving trucks through the crowds, as hundreds scrambled over partly destroyed shops grabbing anything they could. As he ran from the scene with a big box of tampons, Love Zedouni shouted: "I've got no idea what this is, but I'm sure you can sell it."
Police used tear gas to scatter looters at street markets near the collapsed presidential palace. At the Cite Soleil slum, moments after police drove by, a reporter spotted a gunman stealing a bag of rice from a motorcycle rider.
"This is one of the most serious crises in decades," U.N. Secretary-General Ban Ki-moon said as he flew into the Haitian capital. "The damage, destruction and loss of life are just overwhelming."
A reliable death toll may be weeks away, but the Pan American Health Organization estimates 50,000 to 100,000 died in the 7.0-magnitude tremor, and Haitian officials believe the number is higher.
Celebrating Mass outside the once-proud pink-and-white cathedral, now a shell of rubble where a rotting body lay in the entrance, the Rev. Eric Toussaint preached of thanksgiving to a small congregation of old women and other haggard survivors assembled under the open sky.
"Why give thanks to God? Because we are here," Toussaint said. "What happened is the will of God. We are in the hands of God now."
Mondesir Raymone, a 27-year-old single mother of two, was grateful. "We have survived by the grace of God," she said.
But others were angry.
"It's a catastrophe and it is God who has put this upon us," said Jean-Andre Noel, 39, a computer technician. "Those who live in Haiti need everything. We need food, we need drink, we need medicine. We need help."
Were his parishioners being helped? Toussaint was asked. "Not yet," he replied.
The U.N. World Food Program was "pretty well on target to reach more than 60,000 people today," up from 40,000 the previous day, WFP spokesman David Orr said. But U.N. officials said they must raise that to 2 million within a month. The U.S. aid chief, Rajiv Shah, told "Fox News Sunday" he believed the U.S. distributed 130,000 "meals ready to eat" on Saturday, but the need was much larger. "We're really trying to address it," he said.
In a further sign of the delays, the aid group CARE had yet to set a plan for distributing 38 tons of WFP high-energy biscuits in outlying areas of Haiti, CARE spokesman Brian Feagans said Sunday. He did not say why.
The Geneva-based aid group Doctors Without Borders put it bluntly: "There is little sign of significant aid distribution."
The "major difficulty," it said, was the bottleneck at the airport, under U.S. military control. It said a flight carrying its own inflatable hospital was denied landing clearance and was being trucked overland from Santo Domingo, almost 200 miles away in the Dominican Republic, delaying its arrival by 24 hours.
French, Brazilian and other officials had earlier complained about the U.S.-run airport's refusal to allow their supply planes to land. A World Food Program official told The New York Times that the Americans' priorities were out of sync, allowing too many U.S. military flights and too few aid deliveries.
The U.S. has completely taken over Port-au-Prince airspace and incoming flights have to register with Tyndall Air Force Base in Florida, said Chief Master Sgt. Ty Foster, Air Force spokesman here.
"You won't have the stray cats and dogs allowed to come into the airspace and clog it up," he said.
On Sunday, WFP spokesman Gregory Barrow in Rome was more positive, speaking of "extremely close cooperation" with the U.S. at the airport. But a coordinator here for Spain's international development agency, Daniel Martin, complained that their aid supplies had been diverted to Santo Domingo, and Doctors Without Borders spokesman Jason Cone said the U.S. military needed "to be clear on its prioritization of medical supplies and equipment."
The on-the-ground U.S. commander in Haiti, Lt. Gen. Ken Keen, acknowledged the bottleneck problem. "We're working aggressively to open up other ways to get in here. The ports are part of that," he said on NBC's "Meet the Press."
The White House said Sunday the U.S. Coast Guard ship Oak had arrived at Port-au-Prince harbor, rendered useless for incoming aid because of quake damage, and use heavy cranes and other equipment to make the port functional.
Other U.S. help was on the way: Some 2,000 Marines should arrive off Haiti on Monday, Keen said, reinforcing 1,000 U.S. troops on the ground.
The general reported "increasing incidents of violence," as a weakened Haitian police force and U.N. peacekeeping contingent were overwhelmed.
In the Port-au-Prince neighborhood of Delmas, a crowd gathered Sunday around the bodies of two accused looters, who had been beaten to death by angry residents. Onlookers said they were among 4,000 prisoners who escaped when the main prison collapsed in the quake.
Angry survivors loitered amid piles of burning garbage in the Bel-Air slum. "White guys, get the hell out!" they shouted in apparent frustration at the sight of more and more foreigners in their streets who were not delivering help.
They also sounded furious with President Rene Preval, who hasn't been seen at a rescue site or gone on radio to address the nation since the quake struck.
"Preval out! Aristide come back!" some shouted, appealing for a return of the populist Jean-Bertrand Aristide, who was ousted in 2004. From his South African exile, Aristide said last week he wants to return to Haiti, but spoke of no concrete plans to do so.
Work went on, meanwhile, perhaps in its desperate final hours, to find survivors buried in the vast rubble of Port-au-Prince.
At the U.N. headquarters destroyed in the quake, rescuers lifted a Danish staff member alive from the ruins, just 15 minutes after Secretary-General Moon visited the site, where U.N. mission chief Hedi Annai and at least 39 other staff members were killed. The rescued man was talking and smiling as he was whisked away for medical treatment. Hundreds of peacekeepers and other U.N. staff remain missing.
And at a collapsed Caribbean Supermarket where search teams from Florida and New York City worked overnight, a policeman reported that three people had been pulled out alive around 6 a.m.
More than 1,700 rescue workers had saved more than 70 lives since the quake, a U.N. spokeswoman said in Geneva.
"There are still people living" in collapsed buildings, Elisabeth Byrs told The Associated Press. "Hope continues."
In such conditions, she said, people might survive until Monday.