BBC News - Yemen unrest: Doubts grow over power-transfer dealDoubts over a deal to end Yemen's political crisis are growing, amid dramatic scenes in the capital, Sanaa.
President Ali Abdullah Saleh reportedly refused to sign the accord - brokered by Gulf nations - to resign within 30 days in exchange for immunity.
The opposition approved the deal on Saturday.
Meanwhile, foreign diplomats had to be airlifted out of the United Arab Emirates embassy in Sanaa, which was besieged by Saleh supporters.
On Sunday, anti-government protesters again held mass rallies in the capital.
Mr Saleh refused to sign the deal unless opposition representatives were present at the ceremony at his palace, reports say.
Yemen's state-run TV later showed leaders of Mr Saleh's ruling party signing the accord, the Associated Press news agency reports. But the president did not sign.