An anti-government protestor demanding the resignation of of Yemeni President Ali Abdullah Saleh, in Sanaa Saturday. Hundreds of thousands of anti-government protesters joined a call for a general strike by the country's opposition leaders. (Muhammed Muheisen/Associated Press)

In a major about-face, Yemen's president has agreed to a proposal which requires him to step down within 30 days, handing power to his deputy in charge in exchange for immunity from prosecution.

Gulf Arab mediators negotiated the deal on Saturday, coming in the wake of increasing protests and military defections. The six-nation Gulf Cooperation Council, which includes Saudi Arabia, has been seeking to broker an end to the crisis.

Demonstrators are demanding President Ali Abdullah Saleh step down immediately.  Saleh, who has been in power for 32 years, has been ignoring demonstrations for the past two months.

In the capital of Sanaa on Friday, crowds filled the five-lane boulevard, marking what many are calling the biggest protest in the past two months.

More than 130 people have been killed by government forces during the unrest. An opposition movement grew after taking inspiration from civil insurrections in Egypt and Tunisia, which toppled leaders in those countries.

According to the draft of the latest proposal, Yemen's parliament would grant Saleh legal protection from prosecution. The president would submit his resignation within 30 days and hand power to his vice president, who is to call for new presidential elections.

Opposition spokesman Mohammed Kahtan described the Gulf Council's proposal as "positive" and said the leaders of the opposition parties have all agreed on it.

Requires swearing an oath to Saleh

However, Kahtan added the opposition rejects the draft proposal's call for the formation of a national unity government within seven days of the signing of the proposal and would like Saleh step down first.

"We would have to swear an oath to Saleh, who has already lost his legitimacy," he noted.

Yemen's parliament, dominated by Saleh's party, also has the power approve or reject his resignation.

Protests continued throughout Saturday. Schools, government offices and private companies shut their doors in response to the Yemeni opposition's call for a general strike.

City squares in at least five provinces are filled with protesters staging sit-ins.

Besides military figures, those abandoning the president have included ruling party members, lawmakers, Cabinet ministers, top diplomats and even Saleh's own tribe.

On Friday, authorities for the first time moved against some of the troops, arresting dozens of soldiers and senior officers for joining protesters, a military official said.