He gave no indication of how the proposals were received by Mr. Assad, who has refused to negotiate with political opponents and has described the uprising as foreign-backed terrorism.

Mr. Annan said he would return to Syria for further discussions but did not specify when. He described the Syrian conflict as enormously complex and said that “any miscalculation that leads to major escalation will have impact in the region which will be extremely difficult to manage.”

The developments came a day after pro-Assad crowds thronged Damascus, bringing it to a near standstill for what the government called a “Global March for Syria,” apparently a bid to pre-empt gatherings by protesters on the first anniversary of the conflict.

Scattered clashes were reported across the country on Friday, including fighting between government forces and army defectors in the Damascus suburbs, but nothing on the scale of the military’s recent assaults on the major centers of anti-Assad protests, notably the northern city of Idlib, the central city of Homs and the southern city of Dara’a, where the uprising began.

The Saudi press agency reported late Thursday that four members of the Saudi-dominated Gulf Cooperation Council — Kuwait, Oman, Qatar and the United Arab Emirates — had joined Saudi Arabia and Bahrain in announcing the closing of their embassies in Damascus.

On Friday, Turkey’s Foreign Ministry said in a statement that Turkish citizens in Syria should leave as soon as possible and that consular services in Damascus would be suspended on March 22. Turkish officials did not rule out the possibility that the embassy might be closed.

The effort to isolate the Syrian government has deepened a division pitting a diplomatic alliance of Western and Arab countries and Turkey against Mr. Assad’s few remaining allies, notably China, Iran and Russia. Several Western countries, including the United States, have closed their embassies in Damascus as their governments press Mr. Assad to step aside as part of a settlement.

In Beirut on Friday, Panos Moumtzis, the United Nations refugee agency’s newly appointed coordinator for the Syrian crisis, said teams from a number of United Nations relief agencies would be touring major cities in Syria next week with the cooperation of the Syrian government to assess the needs. But it remains unclear whether the Syrian authorities will agree with their assessment on the level of need, given the government’s efforts to portray the uprising’s leaders as terrorists and thugs.