LUSHAN, China — Sitting near chunks of concrete, bricks and a ripped orange sofa, Luo Shiqiang told how his grandfather was just returning from feeding chickens when their house collapsed and crushed him to death in a powerful earthquake in southwestern China.

"We lost everything in such a short time," the 20-year-old college student said. His cousin was injured in the collapse, but other family members were spared because they were working in the fields in hard-hit Longmen village in Lushan county.

Saturday's earthquake in Sichuan province killed at least 186 people, injured more than 11,000 and left nearly two dozen missing, mostly in the rural communities around Ya'an city, along the same seismic fault where a devastating quake to the north killed more than 90,000 people in Sichuan and neighboring areas five years ago in one of China's worst natural disasters.

The Lushan and Baoxing counties hardest-hit on Saturday had escaped the worst of the damage in the 2008 quake, and residents there said they benefited little from the rebuilding efforts, with no reinforcements or new evacuation procedures introduced in their remote communities.

Luo said he wished more had been done to make his community's buildings quake-resistant. "Maybe the country's leaders really wanted to help us, but when it comes to the lower levels the officials don't carry it out," he said.

Relief teams flew in helicopters and dynamited through landslides Sunday to reach some of the most isolated communities, where rescuers in orange overalls led sniffer dogs through piles of brick, concrete and wood debris to search for survivors.

Many residents complained that although emergency teams were quick to carry away bodies and search for survivors, they had so far done little to distribute aid. "No water, no shelter," read a hand-written sign held up by children beside a road in Longmen.

"I was working in the field when I heard the explosions of the earthquake, and I turned around and saw my house simply flatten in front of me," said Fu Qiuyue, a 70-year-old rapeseed farmer in Longmen.

Fu sat with her husband, Ren Dehua, in a makeshift shelter of logs and a plastic sheet on a patch of grass near where a helicopter had parked to reach their community of terraced grain and vegetable fields. She said the collapse of the house had crushed eight pigs to death. "It was the scariest sound I have ever heard," she said.

The quake – measured by China's earthquake administration at magnitude 7.0 and by the U.S. Geological Survey at 6.6 – struck shortly after 8 a.m. on Saturday. Tens of thousands of people moved into tents or cars, unable to return home or too afraid to go back as aftershocks continued to jolt the region.

The quake killed at least 186 people, left 21 missing and injured 11,393, the official Xinhua News Agency quoted the provincial emergency command center as saying.

As in most natural disasters, the government mobilized thousands of soldiers and others, sending excavators and other heavy machinery as well as tents, blankets and other emergency supplies. Two soldiers died after their vehicle slid off a road and rolled down a cliff, state media reported.

The Chinese Red Cross said it had deployed relief teams with food, water, medicine and rescue equipment to the disaster areas.

U.N. Secretary-General Ban Ki-moon said the United Nations stood ready "to provide assistance and to mobilize any international support that may be needed," according to a statement released by the U.N. spokesperson.

In his condolence message, Ban said he "is deeply saddened by the loss of life, injuries and destruction" caused by the earthquake and aftershocks that struck Sichuan province.

Lushan, where the quake struck, lies where the fertile Sichuan plain meets foothills that eventually rise to the Tibetan plateau and sits atop the Longmenshan fault, where the 2008 quake struck.

The seat of Lushan county has been turned into a large refugee camp, with tents set up on open spaces, and volunteers doling out noodles and boxed meals to survivors from stalls and the backs of vans.

A large van with a convertible side served as a mobile bank with an ATM, military medical trucks provided X-rays for people with minor injuries, and military doctors administered basic first aid, applying iodine solution to cuts and examining bruises.

Patients with minor ailments were lying in tents in the yard of the hospital, which was wrecked by the quake, with the most severely injured patients sent to the provincial capital. With a limited water supply and buildings inaccessible, sanitation is a problem for the survivors.

One of the patients receiving care in the hospital's yard was the son of odd-job laborer Zhou Lin, 22. The baby boy was born a day before the quake struck. Zhou said he was relieved that his newborn son and wife were safe and healthy but was worried about his 60-year-old father and other relatives who have been unreachable in Baoxing.

"I can't get through on the phone, so I don't know what's going on there and they don't know if we are all right," he said.

Every so often, an aftershock struck, shaking windows of buildings and sending murmurs through the crowds.

Loading Slideshow...
  • Residents reach for food handouts after a magnitude 7.0 earthquake hit Lushan, Sichuan Province on April 21, 2013. Thousands of rescue workers combed through flattened villages in southwest China in a race to find survivors from a powerful quake as the toll of dead and missing rose past 200. (MARK RALSTON/AFP/Getty Images)

  • Four elderly women walk past damaged buildings after a magnitude 7.0 earthquake hit Lushan, Sichuan Province on April 21, 2013. (MARK RALSTON/AFP/Getty Images)

  • A family stay in a temporary shelter after their home was damaged by a magnitude 7.0 earthquake hit Lushan, Sichuan Province on April 21, 2013. (MARK RALSTON/AFP/Getty Images)

  • Local residents get water from a supply station after the earthquake in Longmen township in Ya'an, southwest China's Sichuan province on April 21, 2013. (STR/AFP/Getty Images)

  • CHENGDU, CHINA - APRIL 21: The earthquake survivors carry the water on April 21, 2013 in Lushan of Ya An, China. (Feng Li/Getty Images)

  • CHENGDU, CHINA - APRIL 21: Rubble from a collapsed building after a strong earthquake hit Southwest China's Sichuan Province on April 21, 2013 in Lushan of Ya An, China. (Feng Li/Getty Images)

  • CHENGDU, CHINA - APRIL 21: Medical officers treat a little patient at the hospital on April 21, 2013 in Lushan of Ya An, China. (Feng Li/Getty Images)

  • Rocks from a landslide that blocked a road are pictured the day after a magnitude 7.0 earthquake hit Lushan, Sichuan Province on April 21, 2013. (MARK RALSTON/AFP/Getty Images)

  • Chinese soldiers search for survivors after a magnitude 7.0 earthquake hit Lushan, Sichuan Province on April 21, 2013. (MARK RALSTON/AFP/Getty Images)

  • A mother carries her baby through rubble after a magnitude 7.0 earthquake hit Lushan, Sichuan Province on April 21, 2013. (MARK RALSTON/AFP/Getty Images)

  • Survivors and rescuers make their way along a damaged road after an earthquake hit Lushan County in Ya'an City, southwest China's Sichuan province on April 21, 2013. (STR/AFP/Getty Images)

  • Rescuers make their way along a street in search for survivors after an earthquake hit Lushan County in Ya'an City, southwest China's Sichuan province on April 21, 2013. (STR/AFP/Getty Images)

  • Survivors make their way along a damaged road after an earthquake hit Lushan County in Ya'an City, southwest China's Sichuan province on April 21, 2013. (STR/AFP/Getty Images)

  • Medical personnel treat survivors for minor injuries at a relieve center after an earthquake hit Lushan County in Ya'an City, southwest China's Sichuan province on April 21, 2013. (STR/AFP/Getty Images)

  • A family cook and eat their dinner outside the makeshift tents housing survivors after an earthquake hit Lushan County in Ya'an City, southwest China's Sichuan province on April 21, 2013. (STR/AFP/Getty Images)

  • A family rest in a makeshift shelter after an earthquake hit Lushan County in Ya'an City, southwest China's Sichuan province on April 21, 2013. (STR/AFP/Getty Images)

  • An elderly couple receives medical treatment after a magnitude 7.0 earthquake hit Lushan, Sichuan Province on April 21, 2013. (MARK RALSTON/AFP/Getty Images)

  • This picture taken on April 20, 2013 shows medical personnel heading for Yaan from Beijing with relief supplies after an earthquake of 7.0 hit the city of Ya'an, southwest China's Sichuan province in the early morning of April 20. (STR/AFP/Getty Images)

  • This picture taken on April 20, 2013 shows college students praying for people at their campus in Hengyang, central China's Hunan province, after an earthquake of 7.0 hit the city of Ya'an, southwest China's Sichuan province in the early morning of April 20. (STR/AFP/Getty Images)

  • In this photo released by China's Xinhua news agency, rescuers save an injured woman after an earthquake hit Baosheng Township in Lushan County, Ya'an City, southwest China's Sichuan Province, Saturday, April 20, 2013. The powerful earthquake struck the steep hills of Sichuan province Saturday, nearly five years after a devastating quake wreaked widespread damage across the region. (AP Photo/Xinhua, Jiang Hongjing) NO SALES

  • In this photo released by China's Xinhua news agency, residents stand outside their house damaged by an earthquake in Longmen Township, Lushan County, Ya'an City of southwest China's Sichuan Province, Saturday, April 20, 2013. The powerful earthquake struck the steep hills of Sichuan province Saturday, nearly five years after a devastating quake wreaked widespread damage across the region. (AP Photo/Xinhua, Zhang Xiaoli) NO SALES

  • In this photo released by China's Xinhua news agency, residents sit next to the ruins of houses destroyed by an earthquake in Longmen Township, Lushan County, Ya'an City of southwest China's Sichuan Province, Saturday, April 20, 2013. The powerful earthquake struck the steep hills of Sichuan province Saturday, nearly five years after a devastating quake wreaked widespread damage across the region. (AP Photo/Xinhua, Zhang Xiaoli) NO SALES

  • In this photo released by China's Xinhua news agency, people carrying their belongings walk in quake-damaged Gucheng Village, Longmen Township, Lushan County, southwest China's Sichuan Province, Saturday, April 20, 2013. A powerful earthquake struck the steep hills of Sichuan province Saturday, nearly five years after a devastating quake wreaked widespread damage across the region. (AP Photo/Xinhua, Fei Maohua) NO SALES

  • In this photo released by China's Xinhua news agency, people carrying their belongings walk in quake-damaged Gucheng Village, Longmen Township, Lushan County, southwest China's Sichuan Province, Saturday, April 20, 2013. A powerful earthquake struck the steep hills of Sichuan province Saturday, nearly five years after a devastating quake wreaked widespread damage across the region. (AP Photo/Xinhua, Fei Maohua) NO SALES

  • Chinese Premier Li Keqiang, center, shakes hands with one of rescuers as he visits a site damaged by an earthquake at a village in Lushan county, Ya'an, southwest China's Sichuan province Saturday, April 20, 2013. The powerful earthquake struck the steep hills of China's southwestern Sichuan province Saturday, nearly five years after a devastating quake wreaked widespread damage across the region. (AP Photo) CHINA OUT

  • A village woman reacts after her house was damaged by an earthquake in Lushan county, Ya'an, southwest China's Sichuan province on Saturday, April 20, 2013. The powerful earthquake struck the steep hills of China's southwestern Sichuan province Saturday, nearly five years after a devastating quake wreaked widespread damage across the region. (AP Photo) CHINA OUT

  • Li Keqiang

    Chinese Premier Li Keqiang, center, is escorted by officials and rescuers as he visits a site damaged by an earthquake at a village in Lushan county, Ya'an, southwest China's Sichuan province Saturday, April 20, 2013. The powerful earthquake struck the steep hills of China's southwestern Sichuan province Saturday, nearly five years after a devastating quake wreaked widespread damage across the region. (AP Photo) CHINA OUT