International mediator Kofi Annan said on Friday, June 29 he is "optimistic" that ministerial crisis talks on Syria's conflict being held on Saturday would produce an acceptable outcome, Reuters reported.

"I think we are going to have a good meeting tomorrow (Saturday). I am optimistic," Annan told Reuters Television in Geneva as he arrived for preparatory discussions due to begin at 0900 GMT.

The talks being held by foreign ministers of major powers and regional players in the Swiss city will end "with an acceptable result", he said, without giving details.

Russia proposed changes on Thursday to his plan for a national unity government in Syria, despite initially supporting it, but the United States, Britain and France rejected the amendments, Western diplomats said.

The suggested changes are related to Moscow's refusal to support the ouster of Syrian President Bashar al-Assad, diplomats in New York said on condition of anonymity.

Annan's spokesman Ahmad Fawzi told Reuters: "The talks are on course and the preparatory meeting is going ahead this morning (Friday)."

Western and Arab diplomats said that the preparatory meeting of senior officials would be key to paving the way to consensus on the prickly issue of political transition in Syria.

But Assad on Thursday dismissed the notion of any outside solution to the 16-month-old uprising against his rule.

"We will not accept any non-Syrian, non-national model, whether it comes from big countries or friendly countries. No one knows how to solve Syria's problems as well as we do," Assad said.