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."