* Annan says Assad cannot resist change
* Syrian government responds to envoy's peace plan
* Former U.N. chief heads for China after Russia
By Thomas Grove
MOSCOW, March 26 U.N.-Arab League envoy Kofi Annan said on Monday that Syrian President Bashar al-Assad's government could not resist the "winds of transformation" but said it was too early to introduce a timeline for a peaceful solution.
Annan spoke at a Moscow airport before departing for Beijing on the second leg of a trip designed to shore up support for his peace mission from the two nations that have been Assad's strongest backers in a year of bloodshed.
"It is not practical to put forth timetables and timelines when you haven't got agreement from the parties," Annan, who met Russian President Dmitry Medvedev and Foreign Minister Sergei Lavrov on Sunday, told journalists.
"This cannot be allowed to drag on indefinitely and as I have told the parties on the ground, they cannot resist the transformational winds that are blowing."
Syria is Russia's firmest foothold in the Middle East, buying billions of dollars worth of weapons and hosting a Mediterranean supply and maintenance facility that is Russia's only naval base outside the former Soviet Union.
Annan said however Russia was "determined to work with me and the parties to bring about a peaceful solution," and that he hoped to receive similar signals of support in Beijing.
Russia and China have shielded Assad from U.N. Security Council condemnation by vetoing two Western-backed resolutions over the bloodshed, in which the United Nations says government forces have killed more than 8,000 people.
However, both countries approved a non-binding Security Council statement last week endorsing Annan's mission, and Russia has lately criticised Assad's handling of the crisis.
The former U.N. chief is promoting a peace plan that includes demands for a ceasefire, the immediate withdrawal of heavy armour from residential areas, access for humanitarian aid and a political dialogue between the government and opposition.
Annan's spokesman said on Monday Syria has formally responded to the six-point plan, but did not give any details.
"Mr Annan is studying it and will respond very shortly," his spokesman Ahmad Fawzi said in a statement.
Annan said it was time for Syria to change: "The only way to deal with this is through reform, through change, change that respects individual human dignity, rule of law and human rights."
He said: "We have asked the government to take the initial steps as a gesture of goodwill to its own people ... and accept the cessation of hostilities."
Annan added that as part of the peace process a U.N. observer force might travel to Syria to "ensure that the parties would honour and respect the commitments they are going to make".
Medvedev offered Russia's full support for Annan's peace efforts on Sunday, but Russian officials suggested foreign backing of Assad's foes was the main obstacle to peace.
Annan said Russia's Foreign Ministry "is prepared to work with me not only in support of the plans and proposals I have put on the table but also in encouraging the parties to move in the same direction and work with me in order to settle this issue peacefully".