Syria's government has told international envoy Kofi Annan that it accepts his six-point plan to end conflict in the country, Annan's spokesman said during talks in Beijing on Tuesday.

"Mr. Annan has written to President Assad urging the Syrian government to put its commitments into immediate effect," spokesman Ahmad Fawzi wrote in a statement from the Chinese capital.

Annan, the joint envoy of the United Nations and the Arab League, arrived in Beijing earlier Tuesday after a trip to Moscow. He has been trying to shore up support from Russia and China, who have been blocking UN Security Council resolutions on Syria.

His plan calls for ending the year-long violence with a UN-supervised ceasefire, unfettered humanitarian aid access to Syrians caught in the conflict, the release of those detained in the unrest and the launch of an inclusive, Syrian-led process leading to a multi-party political system.

"Mr. Annan has stressed that implementation will be key, not only for the Syrian people, who are caught in the middle of this tragedy, but also for the region and the international community as a whole," Fawzi said.

Despite disagreeing with Western handling of the Syrian crisis, Russia and China back Annan's six-point plan.

Premier Wen Jiabao told Annan on Tuesday that China supported his mediation in Syria and believed it would lead to a "fair, peaceful and appropriate" resolution of the conflict there.

The conflict in Syria had reached a "critical stage" and had drawn "close attention from the international community," state media quoted Wen as saying during a meeting with Annan at Beijing's Great Hall of the People.

Annan told Wen that his mission in Syria would be "long and arduous" and needed more international support, according to the official Xinhua news agency.

Chinese Foreign Ministry officials also planned to discuss "political solutions to the Syrian crisis" with Annan, the ministry had said before his two-day visit.

After similar talks Monday in Moscow, Annan said Syrian President Bashar Assad might have to leave "in the end" as part of a settlement of the year-old conflict in the country.

"That is one of the issues the Syrians will have to decide," Annan said in Moscow. "Our effort is to help the Syrians come to the table and find a way out of all this."

China had already voiced broad support for Annan's diplomatic efforts to end the violence in Syria, where by UN estimates more than 8,000 people have died since March 2011.

In Syria meanwhile, heavy clashes raged between rebels and regular army troops throughout the night and into the early hours of Tuesday in areas on the outskirts of Damascus.