US Secretary of State Hillary Clinton says there has been substantial progress on a new nuclear disarmament deal with Russia.
On her visit to Moscow, Mrs Clinton said she believed a final agreement on a new Strategic Arms Reduction Treaty (Start) should be finalised soon.
The nations are trying to replace the 1991 treaty that expired in December, the BBC reports.
Russian Foreign Minister Mr Lavrov said at a joint press conference with Mrs Clinton that Moscow and Washington were in the final stage of a new treaty.
The US is said to have more than 2,000 nuclear weapons, while Russia is believed to have nearly 3,000. Both sides have agreed to cut the number of warheads they hold to between 1,500 and 1,675 each.