WASHINGTON (AP) - Twenty-four hours after distancing itself from a Russian proposal to secure Syria's chemical weapons, the State Department moved Tuesday to claim co-ownership of the idea, which the U.S. says President Barack Obama and the Russian president first discussed last year. Russia's unexpected announcement came Monday after Secretary of State John Kerry said that Syrian President Bashar Assad could avert a U.S. strike on his country by turning "over every single bit of his chemical weapons to the international community in the next week." The State Department initially downplayed Kerry's remarks, which came at a news conference in London, dismissing them as a rhetorical flourish. But as support for the Russian idea snowballed, administration officials retooled their message. By Tuesday, Kerry seemed to say it wasn't a verbal misstep at all. He told a House panel: "Yesterday, we challenged the regime to turn them over to the secure control of the international community so that they could be destroyed." The mixed messages set off a daylong flurry of confusion and, as it turns out, Obama and Russian President Vladmir Putin first discussed the idea last year at an economic meeting in Mexico for world leaders. Still, Kerry's comments in London went viral and spawned headlines about how an off-the-cuff remark might stop a U.S. military strike against Assad's regime. They also came as a surprise to Obama administration officials who were working on the Syria portfolio back in Washington. Confused, they scrambled to mount a damage-control message to tamp down the idea that the administration was making an offer to Assad to avoid military action. The same frenzy played out on Kerry's plane en route back to Washington. A senior State Department official told reporters Kerry and Lavrov talked on the plane. The official, who spoke on condition of anonymity because the official wasn't authorized to discuss the sensitive diplomatic issues by name, said Kerry expressed serious skepticism, given the scale and complexity of the Syrian chemical weapons program. Kerry told Lavrov that the U.S. was not going to "play games," but that if a serious proposal was presented, the U.S. would be willing to review it, the official said, adding that the U.S. had not seen any formal proposal. Kerry also made clear to Lavrov that the Russians could not go to the Syrians and say they were issuing their proposal jointly with the U.S. Syria quickly embraced the idea. France, Britain and U.N. Secretary-General Ban Ki-moon welcomed it. And by the end of the day, Obama, though expressing deep skepticism, declared it a "potentially a significant breakthrough" that could head off the threats of U.S. air strikes. The State Department said that Kerry, Lavrov and Putin spoke about the idea during Kerry's visit to Moscow in April. Over a lengthy dinner at Russia's Ministry of Foreign Affairs, Kerry and Lavrov talked about replicating the Libyan model. The late Libyan leader Moammar Gadhafi voluntarily agreed to give up his weapons of mass destruction, including chemical weaponry, in 2003 following extended secret negotiations between his government, British and former President George W. Bush's administration. The logistics of shutting down Assad's chemical weapons, however, are complicated and the State Department said Russia never presented a formal proposal. Kerry and Lavrov have spoken nine times since the Syrian crisis deepened after the Aug. 21 chemical attack in Syria that killed 1,400 people, including 400 children. Obama and Putin also discussed it at the Group of Eight meeting earlier this month in St. Petersburg, Russia. "President Obama and President Putin began a discussion as leaders were mingling with each other at the end of the meeting," the State Department said. They then decided to go into a corner of the room, where they sat down and spoke for 20 to 30 minutes. Putin broached the idea that had been discussed in previous meeting about reaching an international agreement to remove chemical weapons. Obama agreed that could be an avenue for cooperation, and said that Kerry and Lavrov should follow up on the concept to shape a potential proposal. At the same time the U.S. says it is open to the Russian idea, Kerry and other officials want to see the details and want to see them fast. "It cannot be a delay tactic," Kerry told members of House panel. "I have in several conversations with Foreign Minister Lavrov, that this cannot be a process of delay, this cannot be a process of avoidance, that is has to be real, it has to be measurable, tangible," Kerry said. And it is exceedingly difficult - I want everybody here to know - to fulfill those conditions. But we're waiting for that proposal, but we're not waiting for long. Associated Press Diplomatic Writer Matthew Lee contributed to this report.