"The Syrian people are the only ones who can choose their leader, and who can decide on Syria's present and future," the foreign ministry said.
While the ministry did not specifically address the conclusions of a meeting of supporters of Syria's opposition in London on Tuesday, it said "the Syrian people will not allow any foreign party to impose itself … in choosing a government, or in determining its powers and tasks."
The ministry statement comes amid preparations for a peace conference dubbed Geneva 2, which was first proposed by the United States and Russia and would bring government and opposition representatives to the negotiating table.
"Syria reiterated it is ready to go to the Geneva 2 conference, and to try its best to ensure its success without any preconditions or any foreign intervention," the ministry said.
The opposition has insisted that any talks with regime representatives should lead to Assad's departure.
But the Syrian authorities have said there should be no preconditions for such talks and on Monday, Assad said he is willing to run for re-election when his term ends in 2014.
Assad had also said he would not negotiate with the exiled opposition, and that "the factors are not yet in place" for peace talks.
