President Ali Abdullah Saleh has left his battered nation on his way to the US for medical treatment after passing power to his deputy and asking for forgiveness for any "shortcomings" during his 33-year rule.
But in a sign that Mr Saleh's role as Yemen's top power broker is likely far from over, the 69-year-old said he would return to Yemen before the official power transfer next month to serve as the head of his ruling party.
Protesters took to the streets to protest an immunity deal he brokered in the transfer of power to Vice President Abed Rabbo Mansour Hadi, saying they want to see Mr Saleh tried for his alleged role in the protester deaths.
Mr Saleh's departure on Sunday marks a small achievement in the months of diplomatic efforts by the US and Yemen's Gulf neighbours to ease the nearly year-old political crisis in the Arab world's poorest country. An active al-Qa'ida branch there has taken advantage of the turmoil, stepping up operations and seizing territory.
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After months of diplomatic pressure and mass protests calling for his ouster, Mr Saleh signed a deal in November to transfer authority to his vice president in exchange for immunity from prosecution. Still, Mr Saleh continued to exercise power behind the scenes, sparking accusations he sought to scuttle the deal and cling to power.
His departure could help the deal go forward.
Presidential spokesman Ahmed al-Soufi said that Mr Saleh left Yemen's capital Sanaa late on Sunday on a plane headed for the Gulf sultanate of Oman. He left the Omani capital Muscat last night after a brief layover and was en route to New York.
A senior administration official said Mr Saleh would probably stay in the US until no later than the end of next month. US officials believe Mr Saleh's exit from Yemen could lower the risk of disruptions in the lead-up to presidential elections planned there on February 21.
The Obama administration faced a dilemma in deciding whether to let Mr Saleh enter the US after he requested a visa last month. It has long seen getting Mr Saleh out of Yemen as an important step in ensuring the power transfer goes forward.
But some in the administration worried that welcoming Mr Saleh would spark charges from the Arab world that the US was harbouring an autocrat responsible for deadly crackdowns on protesters.
To protect against this, the administration has sought assurances that Mr Saleh will not seek to remain in the US.
Mr Saleh is likely seeking treatment for injuries sustained in a blast in his palace mosque last June 3 that left him badly burned. After the attack, he travelled to Saudi Arabia for treatment, leaving many to suspect his power was waning. A few months later, however, he made a surprise return to Yemen and resumed his post.
Under the power transfer deal signed in November, Mr Hadi is to be rubber-stamped as the country's new leader in presidential elections. The political parties that signed the deal agreed not to nominate any other candidates.
In a farewell speech on Friday reported by Yemeni state media, Mr Saleh said he was passing his powers to Mr Hadi.
Mr Saleh portrayed himself as a patriot who "gave his life in the service of the nation," called for reconciliation and apologised for any mistakes.
"I ask for forgiveness from all sons of the nation, women and men, for any shortcomings during my 33 years in office," he said.
He also called on Yemen's youth, who have spearheaded the mass protests calling for his ouster and often faced deadly crackdowns by Saleh's security forces, to go home.
"I feel for you and call on you to return to your homes and turn a new page with a new leadership," he said.
Yemen expert Gregory Johnsen of Princeton University said Mr Saleh's departure could help the power transfer deal progress, though it will do little to address protesters' demands for a fundamental change of how politics in Yemen works.
"I don't think we have seen the last of President Saleh," he said.
Inspired by popular uprisings elsewhere in the Arab world, Yemenis took to the streets nearly a year ago to demand Mr Saleh's ouster and call for democratic reforms. Mr Saleh's security forces have met them with often deadly crackdowns, killing more than 200 protesters. Many others have been killed in violent clashes between armed groups that support the protesters and security forces.
Al-Qaida's active Yemeni branch has also taken advantage of the security collapse to seize territory in the country's south, even taking control of a town 100 miles from the capital Sanaa earlier this month.