Yemen's President Ali Abdullah Saleh has signed a Gulf initiative that calls for him to transfer power to a deputy, a move designed to end months of swelling protests against his 33-year rule.

Mr. Saleh signed the agreement, crafted by the Gulf Cooperation Council, during a ceremony in Saudi Arabia Wednesday.

Under the plan, Mr. Saleh is handing power to Vice President Abed Rabbo Mansour Hadi, who is to begin the process of forming a national unity government. The plan also calls for an early presidential election.

After signing the document, Mr. Saleh said his government welcomes the partnership with what he called “brothers in the opposition” to rebuild and reconstruct Yemen.

However, the agreement has not satisfied anti-government demonstrators in Yemen. After the document was signed, protesters gathered in Sana'a to voice their displeasure with a provision that gives Mr. Saleh immunity from prosecution. Also, some called for his immediate departure.

U.N. Secretary-General Ban Ki-moon says Mr. Saleh told him he planned to travel to New York for medical treatment after signing the deal.

On three previous occasions, Mr. Saleh indicated a willingness to sign the GCC plan. However, each time he backed away at the last minute.

Yemeni opposition activists have been holding mass protests since January demanding an immediate end to Mr. Saleh's autocratic rule.

Hundreds of people have been killed and thousands more wounded during a government crackdown on the protests and fighting between pro-Saleh troops and opposition militiamen.

Al-Qaida-linked militants have seized control of several parts of southern Yemen as the government has struggled to contain unrest in other regions.