Syria's government has agreed to accept the peace plan put forward by the United Nations and Arab League envoy Kofi Annan, his spokesman has said.
Ahmed Fawzi said Mr Annan considered it an "important initial step" to help bring an end to the violence, but added that implementation was key.
However, the main opposition coalition is sceptical and has questioned whether the government will honour its pledge.
Meanwhile, the UN said more than 9,000 people had been killed in the uprising.
The acceptance of the plan was hailed as an "important step" by US state department spokeswoman Victoria Nuland.
However, she said Mr Assad must implement the plan by "silencing his guns and allowing humanitarian aid to get in".
Speaking after it was announced that the Syrian government had accepted his peace plan, Mr Annan thanked countries that have supported his attempts to mediate in the conflict.
He is currently in Beijing for talks with Chinese Premier Wen Jiabao.
Mr Wen offered his support for Mr Annan's strategy, saying the situation was "at a critical juncture", and "your mediation efforts will lead to progress".
At the weekend Russia also offered its support. The two countries had been heavily criticised after vetoing two UN Security Council resolutions condemning the violence.
Mr Annan's six-point plan calls for Mr Assad's government to pull troops and heavy weapons out of population centres, and for all parties to allow for a daily two-hour pause to the fighting in order for humanitarian aid to reach affected areas. The plan also requests that the authorities release those detained in the uprising.
However, it does not impose any deadline for Mr Assad, or call for him to leave power.
The main opposition coalition, the Syrian National Council (SNC), which is seeking to agree a "national pact" of common objectives with other opposition groups in Istanbul, gave a lukewarm response to the plan.
"A peaceful transition means that the regime needs to be changed. And that starts with the removal of the head of the state," Basma Kodmani, a spokeswoman for the SNC, told the Reuters news agency.
"Mr Annan's initiative for us should lead to developments of clear terms of reference for negotiation on the modalities of change. Not on whether the change should happen or not."
Mr Annan has written to Mr Assad urging him to put his commitments into immediate effect.
the BBC's Middle East editor Jeremy Bowen says the agreement is not as strongly worded as earlier UN resolutions, but it can be regarded as more pressure on Mr Assad and his government, which he seems to have decided that he cannot ignore.
However, implementing the plan is another matter, our correspondent adds.
In other developments on Tuesday:
- Clashes between Syrian security forces and armed rebels have spilled across the border with Lebanon, witnesses and Lebanese security officials say
- Syria's opposition groups are meeting in Istanbul to try to achieve a more united front
- President Bashar al-Assad has visited the former rebel stronghold Baba Amr in Homs, which troops entered earlier this month after nearly four weeks of bombardment left an estimated 700 people dead
- Yakin Erturk has resigned from a UN commission of inquiry looking into alleged human rights abuses, citing lack of access to Syria
- Turkish Airlines is stopping flights to Syria after Turkey's closure of its embassy in Damascus.