Yemeni President Ali Abdullah Saleh is in Riyadh for the signing of a Gulf-sponsored plan for him to hand over power to a deputy and allow the formation of a national unity government that would try to end the country's 10-month-long political crisis.

Mr. Saleh arrived in the Saudi capital, Wednesday. Yemeni state media said he will attend the signing of the Gulf Cooperation Council power-transfer plan and its “implementation mechanism.” The Yemeni president has promised to sign such a plan several times this year, but on each occasion he backed away at the last minute.

U.N. envoy to Yemen, Jamal bin Omar, says Mr. Saleh and the opposition agreed in principle on the GCC initiative on Tuesday. The plan calls for the president to hand power to Vice President Abd-Rabbu Mansour Hadi immediately in return for immunity from prosecution.

Under the deal, Mr. Saleh would retain the honorary title of president while Hadi leads a national unity government until early elections in several months. U.N. envoy Omar was in Sana'a to help mediate the agreement. Speaking Tuesday, he said the details were still being worked out.

Yemeni opposition activists have been staging near-daily mass protests since January to demand an immediate end to Mr. Saleh's 33-year autocratic rule. A government crackdown on the protests and fighting between government troops and opposition militiamen has killed hundreds of people and wounded thousands more.

Witnesses say fighting erupted again Wednesday in northern Sana'a's Hasaba district, with exchanges of fire between pro-Saleh troops and forces loyal to opposition tribal chief Sadeq al-Ahmar. Explosions could be heard in the area, but there were no immediate reports of casualties.

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