A possible diplomatic solution to avoid a U.S. military strike arose Monday when Syria swiftly welcomed a suggestion to turn over all of its chemical weapons for destruction under international control. President Barack Obama said the proposal could be “potentially a significant breakthrough” but he remained skeptical that Syria would follow through.

The White House pressed ahead with efforts to persuade Congress to authorize a military strike, and Obama said the day's developments were doubtless due in part to the “credible possibility” of that action. U.S. officials insisted that Syrian President Bashar Assad's government must be held accountable for using chemical weapons regardless of what happens to its stocks.

But the diplomatic opening could provide Obama with a way out of a messy political and foreign policy bind.  It followed a remarkable chain of events that started with a suggestion from Secretary of State John Kerry, followed by a proposal from Russia and immediate endorsement by the U.N. secretary-general.

Obama told NBC News in an interview Monday that he's taking a statement from Damascus welcoming the idea “with a grain of salt initially.” But he said he would “absolutely” halt a U.S. military strike if Syria's stockpiles were successfully secured.

“My objective here has always been to deal with a very specific problem,” Obama said in an interview with ABC News. “If we can do that without a military strike, that is overwhelmingly my preference.”

The suggestion to secure the chemical weapons “could potentially be a significant breakthrough,” Obama told NBC News in another interview. “But we have to be skeptical because this is not how we've seen them operate over the last couple a years.”

Kerry told reporters in London early Monday that Assad could resolve the crisis surrounding the use of chemical weapons by surrendering control of “every single bit” of his arsenal to the international community by the end of the week.

Hours later, Russian Foreign Minister Sergey Lavrov promised to push its ally Syria to place its chemical weapons under international control and then dismantle them quickly to avert U.S. strikes. Syrian Foreign Minister Walid al-Moallem immediately embraced the proposal.

Then in quick succession, U.N. Secretary-General Ban Ki-moon urged acceptance, British Prime Minister David Cameron said the idea was worth exploring and French Foreign Minister Laurent Fabius said it “deserves close examination.” Former U.S. Secretary of State Hillary Rodham Clinton said any move by Syria to surrender its chemical weapons would be an “important step.”

That seemed to raise prospects for avoiding an expansion of the Syrian civil war, and spokesmen said the Obama administration would take a “hard look” at the proposal.

Obama cast Russia's proposal as a direct result of the pressure being felt by Syria because of the threat of a U.S. strike and warned that he would not allow the idea to be used as a stalling tactic.

“I don't think that we would have gotten to this point unless we had maintained a credible possibility of a military strike, and I don't think now is the time for us to let up on that,” he said.

White House spokesman Jay Carney sidestepped questions on whether the U.S. and Russia had coordinated Monday's proposal, saying only, “There are ongoing conversations on this matter at the highest level.”

Obama said he spoke with Russian President Vladimir Putin last week about a potential plan for Syria to turn over its chemical weapons to international control, and that it was a continuation of previous conversations he's had with Putin on the subject.

Obama told PBS' “NewsHour” that he and Putin spoke about it last week during in economic summit in St. Petersburg, Russia. Obama and Putin had an impromptu chat Friday for about 20 minutes.

Kerry spoke by phone with Lavrov shortly after making his comments in London, and officials familiar with the call said Lavrov had told Kerry that he had seen the remarks and would be issuing a public statement. Kerry made clear that his comments were rhetorical and were not meant to be a proposal, according to the officials. They added that Kerry told Lavrov that the U.S. was not going to “play games,” but the U.S. would be willing to review a serious proposal. They stressed that he made clear that Lavrov could not present the idea as a joint U.S.-Russian proposal.

The officials commented only on condition of anonymity because they were not authorized to describe the information publicly.

The State Department sought to tamp down the potential impact of Kerry's comments by calling them a “rhetorical” response to a hypothetical question and not “a proposal.”

State Department spokeswoman Marie Harf said the U.S. had “serious skepticism” about Syria's statement because it might be merely a stalling tactic. She said Syria had consistently refused to destroy its chemical weapons in the past.

In fact, she said the developments made it even more important for Congress to authorize the use of force against Syria as a means for pushing Assad to actually get rid of chemical weapons stocks.

Obama, who will address the nation Tuesday night, faces a decidedly uphill fight to win congressional backing _ and serious doubts by the American public.

A new Associated Press poll shows a majority of Americans oppose a U.S. strike on Syria. Most of those surveyed said they believe even limited strikes would lead to a long-term military commitment. The poll was released Monday and conducted Sept. 6-8.

The U.S. accuses Assad's government of being behind an attack using sarin gas in a Damascus suburb on Aug. 21, killing 1,429 people. Some other estimates of the deaths are lower, but there is wide agreement that chemical weapons were used.

In an interview broadcast Monday on “CBS This Morning,” Assad denied responsibility, accused the Obama administration of spreading lies without providing a “single shred of evidence,” and warned that air strikes against his nation could bring retaliation. Pressed on what that might include, Assad responded, “I'm not fortune teller.”

Later Monday, Syria's foreign minister, meeting with his Russian counterpart in Moscow, addressed the idea of getting rid of any chemical weapons.

“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,” said al-Moallem.

Russia's proposal provided confirmation from Syria's most important international ally that the Syrian government possesses chemical weapons, and al-Moallem's welcome was a tacit acknowledgment. Syria's foreign ministry last year retracted a threat to use chemical weapons, saying it was not acknowledging that it had them.

U.S. officials in Washington initially said they were surprised by Kerry's comments, which came at a news conference with British Foreign Secretary William Hague and in response to a question about what, if anything, Assad could do to stop the U.S. from punishing it for the use of chemical weapons.

“He could turn over every single bit of his chemical weapons to the international community in the next week,” Kerry said. “Turn it over, all of it, without delay, and allow a full and total accounting for that. But he isn't about to do it, and it can't be done, obviously.” (AP)