Officials in Oman remain tight-lipped about reports that outgoing Yemeni president Ali Abdullah Saleh is seeking exile in the sultanate.

Saleh left Sana'a on Sunday and headed to the United States for medical treatment following a brief stopover in Oman, though he said in a parting speech he would return to Yemen.

However, Saleh who asked for forgiveness for any "shortcomings" during his 33-year reign before departing is said to be seeking a residence in exile under pressure from Washington and Riyadh.

A foreign diplomat in Muscat told the Associated Press that Saleh has sought permission to reside there. However, an Omani government source declined to confirm or deny receiving such a request. The source also indicated Oman would be reluctant to grant Saleh exile because it might harm future relations with Yemen.

Officials in Washington, who endorsed a plan to coax Saleh out of office by granting him immunity for the deaths of protesters during an uprising against his rule, admitted they allowed Saleh to seek treatment in the US to get him out of Yemen.

"We ... believe that his absence from Yemen at this critical juncture will help facilitate a transition that completes the end of his rule, helps Yemen and ultimately has a positive effect on the rights and dignity of the Yemeni people," White House spokesman Jay Carney said on Monday.

"Our policy focus remains on preventing further instability and keeping that transition on track," he said, emphasizing Saleh would stay in the United States for a limited time.

Despite Saleh's departure, popular opinion in Yemen is that his supporters will still wield influence over the country, which has seen a year of anti-government demonstrations and open violence Saleh's forces, army defectors loyal to a rebel general, and tribal militias.

Protesters continue to stage work stoppages and, demonstrations outside the residence of Yemen's acting leader Abd Rabbo Mansour Hadi, calling for former Saleh confidants to be dismissed from the acting unity government. The government in Sana'a is currently divided equally between opposition figures and holdovers from Saleh's reign.

The strike is part of a wave that has gripped Yemen over the past month, after Saleh signed a Gulf-brokered deal formally handing power to his deputy Hadi in November.