Fabius said, however, that the Security Council needs to oversee the process; that it should start immediately; and the plan shouldn't let anyone off the hook for ordering a chemical attack.
At the United Nations, Secretary-General Ban Ki-moon said he is also considering asking the Security Council to demand the Syrian government immediately hand over its chemical weapons to be destroyed. Ban said Monday that if U.N. inspectors confirm the use of chemical weapons in Syria, it would be an "abominable crime" worthy of international response -- but he has previously warned against "further militarization of the conflict" in Syria.
Could a 'goof' be a solution?
A senior State Department official who spoke on condition of anonymity said Kerry and Lavrov were on a previously scheduled call before Kerry flew back from London when Lavrov brought up his remarks.
"I saw your comments this morning," Lavrov said to Kerry, the State Department official said. The Russian foreign minister said he would speak about the issue but played down the idea that a proposal was on the table during the 14-minute conversation, the official said.
Kerry told Lavrov that the United States "is not going to 'play games,'" the official said. "If there is a serious proposal, we will take a look."
One U.S. official called Kerry's remarks a "major goof," adding that America's top diplomat "clearly went off script." And several State Department representatives tried to clarify Kerry's remarks later in the day, calling them a "rhetorical argument."
"His point was that this brutal dictator with a history of playing fast and loose with the facts cannot be trusted to turn over chemical weapons. Otherwise he would have done so long ago," State Department spokeswoman Jen Psaki said. "That's why the world faces this moment."
The prospect of a diplomatic deal is likely going to make the Obama administration's attempts to make a case before Congress even more difficult, said Michael O'Hanlon, a senior fellow at the Brookings Institution. Lawmakers who are already debating whether to pass resolutions authorizing military action now may want to rewrite them, he said.
"It's going to obviously throw a monkey wrench in the gears on a number of things," he said.
But it got a hopeful reception in Congress, where the chairwoman of the Senate Intelligence Committee said she would welcome Syria's chemical disarmament "to prevent an international strike."
"I believe that Russia can be most effective in encouraging the Syrian president to stop any use of chemical weapons and place all his chemical munitions, as well as storage facilities, under United Nations control until they can be destroyed," said Sen. Dianne Feinstein, D-California.
Feinstein's House counterpart, Michigan Republican Rep. Mike Rogers, said Washington should review the Russian proposal to "see if there's any teeth to their bark." And Sen. Bob Corker, R-Tennessee, the ranking Republican on the chamber's Foreign Relations Committee, said the best way to reach a diplomatic solution to the conflict "is for us as a nation to stay strong."
"If it is real, and if Syria is willing to make immediate concrete steps, certainly that's something worth looking at," Corker said. "But it's very difficult to tell if it's that or just a way of creating a fog around this whole issue."
Sen. Jack Reed, a leading Democrat on the Armed Services Committee, said the Lavrov proposal is a "distinct change" in Russia's stance, "going from sort of defenders of the regime to now saying there's a real serious problem with chemical weapons in Syria."
"It is very thoughtful," said Reed, of Rhode Island, who described himself as undecided on Syria. "It goes to the essential objective that we should have, which is to deter the use of chemical weapons. This should not be about trying to settle a civil war raging in Syria."