Russian Foreign Minister Sergei Lavrov on Tuesday warned the West not to take unilateral action on Syria, saying that Russia and China agree that violations of international law and the United Nations charter are impermissible.
Russia and China have opposed military intervention in Syria throughout 17 months of bloodshed and have vetoed three UN Security Council resolutions backed by Western and Arab states that would raise pressure on Damascus to end violence.
Lavrov, cited by Russian news agencies at a meeting with China's top diplomat, was speaking a day after US President Barack Obama said US forces could move against President Bashar Assad if he deploys chemical weapons against rebels trying to overthrow him.
Russia and China base their diplomatic cooperation on "the need to strictly adhere to the norms of international law and the principles contained in the UN Charter, and not to allow their violation," Interfax quoted Lavrov as saying at a meeting with Chinese State Councillor Dai Bingguo.
"I think this is the only correct path in today's conditions," Lavrov said.
In some of his strongest language yet, Obama on Monday bluntly warned Assad of "enormous consequences" if he failed to safeguard his weapons of mass destruction.
"We have been very clear to the Assad regime, but also to other players on the ground, that a red line for us is we start seeing a whole bunch of chemical weapons moving around or being utilized," Obama said. "That would change my calculus."
"We cannot have a situation where chemical or biological weapons are falling into the hands of the wrong people," Obama told an impromptu White House news conference. He acknowledged he was not "absolutely confident" the stockpile was secure.
Obama said the issue was of concern not only to Washington but also to its close allies in the region, including Israel.
Seeking re-election in November, Obama has been reluctant to get the United States involved in another war in the Middle East, even refusing to arm rebels fighting a 17-month-old uprising against Assad.
Syria last month acknowledged for the first time that it had chemical and biological weapons and said it could use them if foreign countries intervene -- a threat that drew strong warnings from Washington and its allies.
Western countries and Israel have expressed fears chemical weapons could fall into the hands of militant groups as Assad's authority erodes.
Israel has said that if Syrian-backed Hezbollah guerrillas used the situation to take control of the weapons, it would "act immediately and with utmost force."
"We're monitoring that situation very carefully. We have put together a range of contingency plans," Obama said when asked whether he envisioned the possibility of using US forces at least to safeguard Syria's chemical arsenal.