WASHINGTON —An unscripted suggestion by Secretary of State John F. Kerry that Syria might avoid a US strike by turning over its chemical weapons raised the possibility of a diplomatic breakthrough Monday, as Russia seized on the remark and pledged to persuade its ally to accept the offer.

Russia’s unexpected overture, followed quickly by Syria’s welcoming response, prompted President Obama to say by day’s end that a US strike could possibly be avoided.

Obama said in an interview with ABC News that if Syria did indeed turn over its chemical weapons, that could “absolutely” result in putting a military strike on hold.


“Let’s see if we can come up with language that avoids a strike but accomplishes our key goals to make sure that these chemical weapons are not used,” he said.

Following the developments, the Senate’s majority leader, Harry Reid of Nevada, announced Monday night that a test vote on the issue slated for later this week would be postponed.

But even with the prospect of a breakthrough, Obama remained wary, continuing to seek support from a reluctant Congress for the authority to launch military strikes against the regime of President Bashar Assad of Syria, believed responsible for using sarin gas on Aug. 21 to kill more than 1,400 civilians.

Obama expressed skepticism that Syria, locked in a 2½-year civil war, would willingly give up its arsenal and said he still plans to make the case for a military strike in a speech to the nation Tuesday night.

“I have to say that it’s unlikely that we would have arrived at that point where there were even public statements like that without a credible military threat to deal with the chemical weapons use inside of Syria,” Obama said on CNN.

The surprise turn of events took place after Kerry made what appeared to be an offhand suggestion during a stop in London.


Speaking at a press conference after a three-day European trip to rally support for a military strike, Kerry was asked whether there was anything Syria could do to head off a US strike. His response: Assad’s regime could avoid punishment if it turned over “every single bit of his chemical weapons to the international community in the next week. Turn it over. All of it, without delay. And allow the full and total accounting for that. But he isn’t about to do it.”

Kerry’s apparently impromptu comments were not intended as a formal ultimatum, aides stressed, but nevertheless were seen as a potential diplomatic turning point.

It was initially unclear whether Kerry made a gaffe, providing an opening for Russia, which has obstructed the United States on Syria at nearly every turn and opposes a military strike.

But Obama indicated it was part of a larger behind-the-scenes effort, saying on CNN that he had spoken directly with President Vladimir Putin of Russia during the G-20 summit on Friday, including on aspects of the proposal that the Russians announced on Monday.

“These are conversations that I’ve had directly with Mr. Putin,” Obama said. “When I was at the G-20, we had some time to discuss this.” Putin had approached Obama during the summit on Friday, pulling up chairs and sitting down to talk for nearly 30 minutes.

On Monday, Russia, which has been a key arms supplier to Assad, jumped at what it saw as a way to derail the American march to war.


“If the establishment of international control over chemical weapons in that country will avoid strikes, we will immediately begin working with Damascus,” Foreign Minister Sergei Lavrov of Russia offered after he watched Kerry’s London press conference. “We call on the Syrian leadership not only to agree on a statement of storage of chemical weapons under international supervision, but also to their subsequent destruction.”

Foreign Minister Walid al-Moallem of Syria, who was in Moscow for consultations, responded that ‘‘Syria welcomes the Russian proposal out of concern for the lives of the Syrian people, the security of our country, and because it believes in the wisdom of the Russian leadership that seeks to avert American aggression against our people.”

It was not clear, however, whether Syria — which has never publicly acknowledged it even has a chemical weapons arsenal — would agree to a proposal to give up its stockpile or allow international inspectors to take custody of it.

But other countries also began signaling support for containing Syria’s chemical weapons instead of a military strike.

France’s foreign minister, Laurent Fabius, who met with Kerry on Saturday in Paris, backed the idea. So did David Cameron, the British prime minister, and the United Nations secretary-general, Ban Ki-moon, who pledged to take the proposal to the Security Council.

It also raised the possibility of a greater role for the United Nations, just days after the US envoy Samantha Power said all diplomatic options had been “exhausted.”


Although administration officials said they would discuss the Russian offer to act as intermediary, they also expressed deep skepticism at the prospects that such a mechanism could prove a viable way to deter the future use of such weapons, which they insisted is the primary goal.

“This is not going to be a quick fix on this issue,” said Phillip Gordon, Obama’s top Middle East adviser on the National Security Council. “We have to be cautious about distraction from the issue at hand” — namely deterring the future use of chemical weapons by Assad’s forces.

On the flight back to Washington, Kerry and Lavrov spoke by phone for about 15 minutes, according to a senior State Department official. Lavrov told Kerry he saw his press conference in London. Kerry aides said the comments were rhetorical, not a formal proposal, which he explained to his Russian counterpart.

“The secretary expressed serious skepticism and said the US is not going to play games,” a State Department official, speaking on the condition of anonymity because he was not authorized to talk on the record, told reporters traveling on Kerry’s plane. “If there’s a serious proposal, then we’ll take a look.”

A number of specialists on Russia and Syria said the Russians were just trying to buy more time for their Syrian allies.

“The Syrian government is not going to give up its stockpile of chemical weapons in a week,” said Andrew Tabler, a specialist on Syria at the Washington Institute of Near East Policy. “It is their primary strategic weapon vis-a-vis Israel.”


“They are not going to get anything out of the Russians on Syria,” said Anna Borshchevskaya, a research fellow at the European Foundation for Democracy in Washington. “The Obama administration doesn’t understand the Russian mentality. With Russia it is a lot of bluster. For Putin, he wants to remain important. He wants the world to see Russia as a country without which international decisions cannot be made.”

Although Kerry’s remark appeared to be offhand, it contained the outline of a deal that has both positive and negative effects for the Obama administration. It could extricate Obama from having to suffer a potentially high-stakes defeat in Congress that could prove devastating on the domestic and worldwide stage.

But it could also give Assad a way to lengthen the civil war in his country while retaining an array of valuable assets — including his air force, communication system, and air defense — that could be destroyed in a US strike, analysts said.

Bryan Bender can be reached at bender@globe.com. Follow him on Twitter @GlobeBender. Matt Viser can be reached at maviser@globe.com.