Russian President Vladimir Putin dismisses US claims that Syria’s regime used chemical weapons, describing them as “utter nonsense”.
Mr Putin challenged Washington to present the evidence behind its claims to the United Nations Security Council.
He added that President Obama, a Nobel Peace Prize laureate, should “consider the potential victims of a military attack on Syria, and any unilateral attack by the US would be “extremely sad”.
Mr Putin said next week’s G20 summit in St Petersburg could be a platform to discuss the Syria crisis, and said he was “surprised” at the UK’s parliamentary decision not to join in any military attack against Assad.
US President Barack Obama has said he is considering military action against Syria based on intelligence reports and an attack could be imminent.
The Russia leader’s remarks came after UN chemical weapons inspectors ended their visit to Syria.
The United States said on Friday it was in the planning process for a limited military response to punish Syrian President Bashar al-Assad for a “brutal and flagrant” chemical weapons attack that it says killed more than 1,400 people in Damascus 10 days ago.
The Syrian government denies using chemical weapons.
Russia, an ally of Assad’s, opposes any military intervention in Syria, warning an attack would increase tensions and undermine the chances of ending the civil war.
It is a permanent member of the UN Security Council, with the power to veto resolutions.
“Washington statements with threats to use force against Syria are unacceptable,” Russian Foreign Ministry spokesman Alexander Lukashevich said in a statement late in Friday.
“Any unilateral use of force without the authorisation of the U.N. Security Council, no matter how ‘limited’ it is, will be a clear violation of international law, will undermine prospects for a political and diplomatic resolution of the conflict in Syria and will lead to a new round of confrontation and new casualties.”
Lukashevich also said that Washington’s threats were made “in the absence of any proof” of the Syrian government using chemical weapons.