SANAA, Yemen — A sea of hundreds of thousands of anti-government protesters swelled along a five-lane boulevard reaching across Yemen's capital Friday in the largest of two months of demonstrations, as the government tried to halt military defections by arresting dozens of officers.
Crowds waving protest banners and the national flag packed a three-mile (five-kilometer) stretch of Sitteen Street and, pausing for the midday Muslim prayer, bowed to the ground together in neat row after row in a startling display of numbers.
The size of the demonstrations calling for President Ali Abdullah Saleh's ouster have grown each Friday, when the main protests of the week are held. People continue to join them despite a crackdown that has killed nearly 130 protesters, including more than 40 who were methodically gunned down in a sniper attack in the capital on March 18.
The killings turned many of Saleh's closest allies against him, including defecting army units that are now guarding the main protest camp in the capital, Sanaa.
Authorities for the first time moved against some of the troops on Friday, arresting dozens of soldiers and senior officers for joining protesters, a military official said.
In comments to supporters Friday, Saleh ridiculed them and other protesters as "cowards" and "renegades."
Besides military figures, those abandoning the president have included ruling party members, lawmakers, Cabinet ministers, top diplomats and even Saleh's own tribe. Still, the president of 32 years has clung to power in the fragile country on Arabia's southern edge, in large part because he still has the support of the best military units under the control of his son Ahmed and other close relatives.
The military official would not identify any of the military figures arrested Friday. Authorities decided to act after a demonstration against the president by dozens of soldiers and airmen at the Anad air base in the southern Lahj province on Tuesday, said the official, a colonel who spoke on condition of anonymity to avoid reprimand for releasing the information.
Two people were killed in new protests across the country on Friday, including 15-year-old Abdel-Hamid Mohammed, who was struck in the eye by a bullet and bled to death, said a medical official in the northern province of Hagga. He spoke on condition of anonymity because he was not allowed to release the information.
The other was a soldier from the Republican Guard, a key force that remains loyal to Saleh. He was killed in clashes with protesters backed by armed tribesmen in Marib, said tribal chief Jaabal Tuaiman. Marib is the main city in an unruly province east of the capital that is also a stronghold of Yemen's active al-Qaida offshoot.
Demonstrating the power of Yemen's armed tribes, the crowds in Marib seized two tanks and set fire to two others as well as a number of other military vehicles, said a military officer, speaking by telephone on condition of anonymity because he was not authorized to brief the media.
None of the military personnel arrested Friday were from the 1st Armored Division, the most important of the military units to defect. Its commander, Maj. Gen. Ali Mohsen al-Ahmar, was a Saleh confidant who joined the uprising on March 21.
He and several other top army commanders have deployed their tanks in the streets of the capital to protect protesters centered around Sanaa University.
Other arrest sweeps have targeted civilian protesters. Among them were two women seized Tuesday by female security agents and forced into a black car that had no license plates but displayed a government symbol on its rear window, said Majed al-Mazhaji, an activist and leading member of the opposition in the capital.
Yemen's protests, which began in early February, have channeled anger at the country's grinding poverty, government corruption and the widespread belief that the president was setting his son Ahmed up to succeed him. Their demands quickly escalated to include Saleh's immediate departure.
A group of Gulf Arab nations, including powerful neighbor Saudi Arabia, is trying to broker an end to the crisis. A draft proposal calls for Saleh to hand over power to a successor of his choosing and leave within a month, safe from the possibility of prosecution.
Neither side has accepted the proposal. Saleh, who early on in the unrest pledged not to run for re-election or set up his son to replace him, is insisting on his constitutional right to serve out his term, which ends in 2013.
In the capital and elsewhere, hundreds of thousands chanted against Saleh Friday.
Opposition activist Walid al-Ammari said the new demonstrations were "a message to this ruler to step down immediately without any promises of immunity from trial."
Outside the presidential palace in Sanaa, a large crowd of Saleh's supporters wore loyalists badges depicting the president.
Addressing his supporters, Saleh repeated his refusal to leave office right away.
"We reject toppling democracy and legitimacy, but we welcome the Gulf initiative and we will deal with it positively according to the constitution," he said.
Saleh described his opponents as "dilapidated, corroded, renegade and cowardly elements," vowing that "we will confront them with steadfastness."
A Muslim prayer leader addressing worshippers in the capital seized on Saleh's use of the word "legitimacy" and asked "what legitimacy is this man talking about?"
"Today's legitimacy is the revolution and not the constitution."