SANAA, Yemen -- Thousands of anti-government protesters held their ground Sunday in the Yemeni capital's Change Square despite the president's acceptance of an Arab proposal to leave office under certain conditions after 32 years in power.
More than two months of protests pressing for President Ali Abdullah Saleh to immediately step down have left him clinging to power and brought down intense international pressure for him to leave office. A bloc of Gulf nations has been trying to broker an end to the crisis, fearing the potential impact of more instability in the fragile country, which is home to al-Qaida's most active branch.
Saleh agreed Saturday to the proposal for him to hand power to his vice president within 30 days of a deal being signed in exchange for immunity from prosecution for him and his sons.
A coalition of seven opposition political parties also agreed to the proposal with several reservations. But they do not control the street, where key figures among a diverse range of other government opponents rejected the proposal and said they doubted Saleh had any intention to leave.
Thousands of protesters held onto their camp in Change Square in the capital, Sanaa, where they are ringed by military units that defected to join and protect them. Men in desert camouflage military uniforms mixed with the crowds, pumping their arms into the air and flashing victory signs.
"The proposals are not acceptable at all and the opposition parties don't represent us," said Khaled al-Ansi, a leader of the youth movement that is one of the main organizers of the street protests.
Al-Ansi said Saleh was "behind everything that is happening and he should be tried together with his sons" for the heavy crackdown on protesters.
More than 130 people have been killed by security forces and Saleh supporters since the unrest began in early February. At least 40 were killed in a single attack on March 18 by rooftop snipers overlooking Change Square.
Days later, a wave of defections by those outraged at the violence picked up pace. Top military commanders, diplomats, ruling party members and even Saleh's own tribe have abandoned him.
Saleh offered earlier in the crisis to step down by the end of the year. When that failed to ease the unrest, he insisted he would stay until the end of his term in 2013. Seeking to ease the international pressure on him, he warned the country would slide into chaos and al-Qaida would seize control if he left early.
The U.S. is concerned about the possibility of a security vacuum as well as political and economic paralysis if Saleh leaves office without a clear deal in place, said a former U.S. ambassador to Yemen, Barbara Bodine.
But she was not worried any new government would partner with al-Qaida.
"I do not think we need to be concerned that a Taliban-like government is going to come in, one that is going to support and facilitate al-Qaida in the Arabian Peninsula," she said in an interview on Saturday night.
Her assessment of the Gulf mediation effort was that it would not bring a quick end to the crisis.
"We are not at the end. We may be at the beginning of the end, but we are not at the end of this process."
In a sign of the kind of instability Yemen faces daily, soldiers and armed tribesmen clashed Sunday over a local dispute in the southern town of Yafei. Four soldiers and one tribesmen were killed, a security official said, speaking on condition of anonymity because he was not authorized to speak to journalists.
There is a huge gap in trust between Saleh and the opposition, said Abdul-Malek al-Mekhlafi, a law professor and an opposition leader.
"The opposition is worried that President Saleh might change his mind at any time," he said.
Fueling their suspicions, the proposal Saleh agreed to by the six-nation Gulf Cooperation Council includes language requiring Yemen's parliament to accept or reject his resignation.
The legislature is packed with members of his party, leaving him with a potential way out or at least a way to stall.
Saleh, a shrewd politician and former military officer, has held power for decades by using his security forces to put down opponents and deftly negotiating with powerful tribes that hold sway in Yemen's remote hinterlands.
He has fended off numerous serious challenges. The country's al-Qaida offshoot has attacked his forces, an armed rebellion has battered the north of the country and a secessionist movement has reappeared in the once-independent south.
At the same time, the country is rapidly running out of water and oil and is the poorest in the Arab world.
The United States has watched the uprising with particular concern because Saleh has been an ally in fighting al-Qaida in the Arabian Peninsula, which has been behind two nearly successful attempts to attack U.S. targets in recent years and has an estimated 300 fighters.
Washington, which has supported Saleh with military and financial aid for battling al-Qaida, is now backing a transition of power to end the crisis. The White House on Saturday urged all parties in Yemen "to move swiftly to implement" a deal transferring power.
The Gulf mediators' proposal calls for the opposition to join Saleh in a national unity government within days of signing a deal.
The seven legal opposition parties involved in the talks say that is unacceptable and they want to see Saleh leave office before any negotiations on joining a unity government.
AP broadcast reporter Martin Di Caro contributed to this report from Washington.