"I am speaking theoretically and hypothetically, but if we become convinced that (Syrian President Bashar) al-Assad is cheating, we can change our position," the Kremlin chief of staff Sergei Ivanov was quoted as saying by Russian news agencies.
He was speaking at a conference in Stockholm organised by the International Institute for Strategic Studies.
Ivanov did not clarify his remarks, and reiterated Russia's opposition to intervention in the country wrought by civil war that has killed over 110,000 in 30 months.
"We still don't know, where the chemical weapons are located geographically. I think this will become clear within a week," Ivanov said.
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The US-Russian plan to dismantle the chemical arms stockpile has helped prevent US-led military action following a chemical attack last month that killed hundreds of people and which Washington blames on the regime.
Under the plan, Assad's regime had until today to supply details of its arsenal.
On the eve of the disclosure deadline, the Organisation for Prohibition of Chemical Weapons said it "has received an initial disclosure from the Syrian government of its chemical weapons programme."
President Vladimir Putin on Thursday said that he "doesn't know" if Russia can convince Assad to destroy his chemical arsenal. "So far, everything looks as if Syria has completely agreed with our proposal," he said, adding that the regime's actions "inspire confidence.