Russia is ‘in theory’ prepared to change its stance on Syria if it finds out that Syrian President Bashar Assad is “cheating,” the Kremlin chief of staff said Saturday, Sept 21, according to RIA Novosti.

“I am talking theoretically and hypothetically here, but if we see any certainty that Assad is cheating, we could change our position,” said Sergei Ivanov, head of Russia’s presidential administration, speaking at the International Institute for Strategic Studies’ Global Strategic Review conference in Stockholm.

On Wednesday, Assad, who denies using sarin gas against his people, pledged to destroy his country’s chemical arsenal, as stipulated by an agreement reached last Saturday between Russia and the U.S. Ivanov described another hypothetical situation: one in which it emerges that both the Syrian government and the opposition have used chemical weapons.

“I can imagine what the global community will do then,” Ivanov said, adding that in the event of such a scenario, Russia would take “only diplomatic action – what else can we do?”

The Kremlin chief of staff warned that the Syrian opposition would entirely lose interest in any future negotiations in the event of external military intervention.

“It will count on the U.S. – like in Libya – bombing the regime until it’s wiped out, and in doing so paving the way of the militants to easy victory,” Ivanov said.

He reiterated that it was the U.S.’s responsibility to get the Syrian opposition to attend talks with the Syrian government that the U.S. and Russia have been trying to organize for several months.

“The assertion that cruise missile strikes will help move along the peace process is not only unrealistic, it’s irresponsible,” Ivanov added.

Meanwhile, the Organisation for the Prevention of Chemical Weapons confirmed that it has received "the expected" account by Syria of its chemical arms program.

"We can confirm that we have received the expected disclosure from the Syrian government regarding its chemical weapons programme," the OPCW said.

On Monday, the UN confirmed in a report that the nerve agent sarin had been used in an attack in the Ghouta district of the capital, Damascus, on Aug 21, killing hundreds of people.

The report did not apportion blame, but the U.S., UK and France have accused Syrian government forces of carrying out the attack, and the U.S. has threatened military action.