MOSCOW — Russia proposed on Monday that Syria hand over its chemical weapons to international control in an attempt to avert a U.S. military attack.

Sergei Lavrov, the Russian foreign minister, told reporters that he had conveyed the idea to Syria at talks in Moscow and expected “a quick and, I hope, a positive answer.” Syria publicly welcomed the idea, but a senior White House official told NBC News that it was no more than a delay tactic.

Russia is an ally of Syria, and Russian opposition is one reason the United States is not working through the United Nations to build support for a strike to punish the Syrian regime for using chemical weapons in its civil war.