SANAA, Yemen — Hundreds of thousands of anti-government protesters packed the streets of cities throughout Yemen Wednesday, demanding the president's ouster and blaming him for a munitions factory blast that left at least 100 people dead.
Enraged men chanted as they walked toward public squares in Sanaa and elsewhere, waving their national black-white-and-red flag. Many sported green bandannas wrapped around their heads, emblazoned with the word "leave," while others scrawled the word on their palms, waving their hands in the air.
Mass protests have been shaking Yemen for weeks, with demonstrators inspired by successful uprisings in Egypt and Tunisia seeking the ouster of their own autocratic ruler, President Ali Abdullah Saleh who has served for 32 years.
Wednesday's demonstrations ratcheted up the pressure, spreading beyond the traditional gatherings in the capital, the port city of Aden and the town of Taiz to include Saada, where Shiite rebels have fought Saleh's forces for years, Marib, an al-Qaida stronghold and the southern province of Abyan where Islamic militants have seized power in some areas.
The militants, loyal to al-Qaida, seized power of two towns, a strategic hilltop and a munitions factory in Abyan this week. The factory exploded on Monday, killing dozens of impoverished residents who were stripping the place bare.
That prompted accusations by Yemen's opposition groups that Saleh effectively helped the militants by allowing the army to pull back from the factory area, letting the terror network take power in order to stoke Western fears that al-Qaida is poised to take advantage of any vacuum left by his departure.
"Without this organized pull out and the planned chaos by the regime, the massacre at the factory would have not happened," an umbrella group of opposition organizations said in a statement.
Youssef Said, a leader in Saleh's ruling Congress Party and a professor at Aden University, denied the allegations. "These accusations are false and are part of the opposition's political maneuvering," he said.
The party called for the president's supporters to stage a massive demonstration on Friday to counter those calling for him to step down.
Saleh has cooperated closely with the U.S. in the battle against Yemen's branch of al-Qaida, which has used areas of Yemen long out of state control to launch attacks including the attempt to bomb a Detroit-bound airliner with a bomb sewn into underwear.
The president has also battled regional rebellions in the north and south.
The opposition fears the U.S. is reluctant, as a result, to pressure Saleh to reform.
Opposition spokesman Mohammed al-Sabri criticized remarks by U.S. Defense Secretary Robert Gates on ABC News' "This Week" in which he said the fall of Saleh's regime could pose a "real problem" for America.
"The remarks are clear indications that the U.S. administration stands by Saleh who gave al-Qaida elements a green light to create chaos in the south to scare the Americans," the opposition spokesman said Wednesday.
Around 100 demonstrators have been killed as security forces try to violently put down the protests, including more than 40 gunned down by snipers on March 18, said Majid al-Madji of the Yemen rights group Shaqayek.
State control in Yemen has diminished sharply this month as massive demonstrations spiraled in major cities and the government pulled police from many towns. Anti-government protesters in other areas pushed out police and soldiers and set up militias for self-defense. The protesters blame Saleh for mismanagement, repression and the fatal shootings of protesters, and say they will not relent until he goes.
Still, a senior opposition member promised that if Saleh stepped down, he would be treated well – a gesture that offered hopes that despite the hardened stances of both sides, there may still be room to maneuver a solution to the political crisis.
Sheik Sadeq al-Ahmar, leader of Yemen's most powerful tribe, Hashid, to which Saleh himself belongs, told U.S. ambassador to Yemen, Gerald Feierstein, that he would guarantee "a safe and honorable departure from power of Saleh provided that there would be no bloodshed."
Al-Ahmar's spokesman, Abdel-Qawi al-Qaisi, said the sheik – who has defected to the opposition – assured the ambassador during their meeting Monday that changes in Yemen would be in line with the aspirations of the youths and the demands of the political parties.
Saleh's stay in power "constitutes a grave danger to Yemen and its people and endangers the region's security and stability," the opposition statement said.
Monday's explosion was apparently set off accidentally after armed men described by residents as religious extremists seized the factory and nearby towns in the mountains southern province of Abyan, where al-Qaida has been active.
The militants reportedly took two armored cars, a tank, several pickup trucks mounted with machine guns and ammunition. Later, dozens of impoverished men, women and children entered the facility and looted anything of valued that remained, including cables, doors and vehicle fuel, according to witnesses.
Residents said later that someone may have dropped a lit cigarette next to explosives at the site.
The Interior Ministry said at least 100 people were killed and 80 injured in the explosion.
Abyan province's deputy governor, Saleh al-Shamsi, told The Associated Press Wednesday that the armed men were "elements belonging to Sanaa and got their orders from there."
Meanwhile, the head of Yemen's Association for Democratic Freedoms and Human Rights, Seif Ali Hassan, expressed concern about the fate of 77 activists who have been detained incommunicado – 14 in Aden and 63 in Sanaa – for more than two weeks.
Associated Press writer Diaa Hadid in Cairo contributed to this report.