SANAA, Yemen -- Yemen's embattled president on Tuesday accused the U.S., his closest ally, of instigating the mounting protests against him, but the gambit failed to slow the momentum for his ouster.
Hundreds of thousands rallied in cities across Yemen in the largest anti-government protests of the past month, including a gathering addressed by an influential firebrand cleric whom the U.S. has linked to al-Qaida.
"Go on until you achieve your demands," Sheik Abdul-Majid al-Zindani told tens of thousands of demonstrators in the capital of Sanaa.
Some warned that the current political turmoil and possible collapse of President Ali Abdullah Saleh's regime could give a further opening to Yemen's offshoot of the global terror network, known as al-Qaida in the Arabian Peninsula. The Yemen branch, believed to have been involved in the attempted 2009 bombing of an American airliner, is seen as particularly active and threatening to the U.S.
Saleh has been a weak but important U.S. ally in the fight against al-Qaida. Yemen gets U. S. military aid and has allowed American drone strikes on al-Qaida targets. Secretary of State Hillary Rodham Clinton visited Yemen in January and urged Saleh to do more.
However, on Tuesday, Saleh seemed to be turning on Washington. In a speech to about 500 students and lecturers at Sanaa University, he claimed the U.S., along with Israel, is behind the protest movement.
"I am going to reveal a secret," he said. "There is an operations room in Tel Aviv with the aim of destabilizing the Arab world. The operations room is in Tel Aviv and run by the White House."
Saleh also alleged that opposition figures meet regularly with the U.S. ambassador in Sanaa. "Regrettably those (opposition figures) are sitting day and night with the American ambassador where they hand him reports and he gives them instructions," Saleh said.
The Obama administration rejected the claims. White House spokesman Jay Carney called on Saleh to focus on implementing the political reforms demanded by his people instead of "scapegoating."
Saleh's relationship with the U.S. has been ambivalent, and he has at times attempted to play down his military alliance with Washington. Anti-U.S. sentiment remains strong in Yemen, as elsewhere in the region, and Saleh's comments appeared to be an attempt to discredit the protesters by suggesting they are serving foreign interests.
"Part of this is putting blame on others, part of it is trying to manage the situation," said Christopher Boucek, an analyst at the Carnegie Endowment for International Peace, a U.S. think tank. "He (Saleh) does not want to feed into grievances that gave rise to the opposition against him, such as being too close to the U.S."
In another attempt to silence critics, Saleh fired five of the country's 22 provincial governors Tuesday, including three who had spoken out against the government's at times violent crackdown on demonstrators.
In London, Britain's Foreign Office summoned a senior Yemeni diplomat to express "deep concern" over the deaths of protesters at rallies. "The government of Yemen should listen to the legitimate grievances of the Yemeni people," the Foreign Office said.
The momentum against the president, who refuses to step down until elections in 2013, has kept growing since protests erupted a month ago -- inspired by successful uprisings in Egypt and Tunisia. He has lost the support of key tribal chiefs and on Tuesday, opposition parties called their supporters into the streets for the first time. Crowds of tens of thousands each were reported in five areas of the country, including in Sanaa.
Saleh's government is widely seen as corrupt, with relatives of the president holding key positions in government and business. Grievances about the growing disparity between Yemen's poor -- nearly half the population of some 23 million -- and a small ruling clique have helped drive the protests. Yemen is the Arab world's poorest country.
In the port city of Aden, the scene of deadly clashes between police and demonstrators last week, thousands rallied Tuesday to express their anger. "We are demonstrating and calling for the downfall of the regime because Aden, under Saleh, has turned into a village," said Faiza al-Sharbary, a 45-year-old teacher. "At one time, it was one of the best cities. Therefore this regime has to leave."
In Sanaa, tens of thousands gathered outside the university, the heart of the protests.
Al-Zindani, the influential Islamic cleric, praised the young protesters, saying their rallies are "a new way to change regimes that we did not know 50 years ago."
"Go on until you achieve your demands," he told them. "You have come out demanding changes as a result of desperation."
Al-Zindani's role appeared unclear.
Saleh, in power for 32 years, has tried to co-opt the preacher, appointing him last year as a mediator between the government and opposition parties over electoral reform.
However, al-Zindani is also thought by the United States to be a one-time spiritual mentor of Osama bin Laden. In the past, the cleric has criticized the U.S.-backed fight against al-Qaida, warning that it could lead to a foreign occupation of Yemen.
Some in Yemen said the current turmoil could strengthen the local al-Qaida branch.
"One of the principal worries of our regional and global partners has been that if Yemen goes into anarchy, the possibility of al-Qaida having easy access should be quite clear," said Mohamed Qubaty, a senior member of Yemen's ruling party.
Yemen has been the site of numerous anti-U.S. attacks, going back to the 2000 bombing of the USS Cole in Aden harbor, which killed 17 American sailors. Late last year, several CIA operatives were targeted in a failed bombing at a restaurant in a Sanaa suburb. Al-Qaida in the Arabian Peninsula was also thought to be behind the attempted bombing of an American airliner landing in Detroit in 2009.
Associated Press writers Matthew Lee in Washington, Raphael Satter in London and Karin Laub in Cairo contributed reporting.