Russian officials have given the United States a plan to put Syria's chemical weapons arsenal under international control, ahead of a key meeting between Moscow and Washington's top diplomats in Geneva, reports said Wednesday.

"We handed over to the Americans a plan to place chemical weapons in Syria under international control. We expect to discuss it in Geneva," Russian news agencies quoted a source in the Russian delegation to the talks as saying.

The source did not provide any further details on the plan.

Russian Foreign Minister Sergei Lavrov and US Secretary of State John Kerry are preparing to discuss on Thursday a Russian plan to collect and destroy Syrian chemical weapons.

Another source told state news agency ITAR-TASS that the meeting in Geneva could last several days.

"It appears that the meeting should start on Thursday and end on Friday, although it is not ruled out that it may last until Saturday," the Geneva-based source was quoted as saying.

"It will be a bilateral meeting, there are no plans to involve the UN."

ITAR-TASS said the meeting was set to take place at one of Geneva's luxurious hotels.

Moscow came forward with the plan earlier this week, prompting US President Barack Obama to postpone his threat to strike Syria in response to an August 21 attack.

According to US intelligence, during that attack Syrian forces killed 1,400 people in rebel-held suburbs of Damascus using sarin gas.