A Russian diplomat signalled on Thursday that Syrian President Bashar Al Assad should refrain from statements suggesting he might seek re-election because it could fuel tension before planned peace talks.
Russia has been Assad's most important international ally during Syria's civil war, but the remarks by Deputy Foreign Minister Mikhail Bogdanov to Interfax news agency appeared to be a rare public criticism of Assad by Moscow.
Assad told Syria's Al Mayadeen television in October that he had no intention of quitting, despite pressure to do so from the United States and rebels fighting government forces. He also saw no obstacles to being nominated for a new term.
"Such rhetorical statements affect the atmosphere and do not make the situation any calmer," Bogdanov was quoted as saying.
Looking ahead to an international peace conference which is planned on Syria next month in Geneva, he said: "Our position is that ahead of the start of negotiations, there should be no remarks that could displease anyone or provoke emotions and a response. They should rather be avoided."
Bogdanov has been involved in preparations for the peace talks that are due to start in Geneva on January 22.
Russia has blocked Western-backed efforts to condemn Assad at the UN Security Council or to push him out of power. Moscow says it is not trying to prop up Assad but that his departure cannot be a precondition for peace moves.