Washington says its U.S. National Security Adviser James Jones' primary aim of visiting Russia is to negotiate a new nuclear arms cuts treaty to replace START 1, RIA-Novosti quoted a spokesman for the White House as saying.
"They're going to, I think, primarily to continue our discussions on renewing our START treaty... continue to make progress and get an agreement on something that we can sign this year to further cut the number of nuclear weapons that each side has," Robert Gibbs said.
The Kremlin said on Saturday the Russian and U.S. presidents hoped a treaty on nuclear arms cuts to replace START 1 would be ready by early December.
U.S. National Security Adviser Jones is expected to be in Moscow on October 28.
The Strategic Arms Reduction Treaty, the pillar of Russian-US disarmament commitments, expires on December 5.
The latest round of talks took place in Geneva two weeks ago.
The outlines of the new pact were agreed during the presidents' bilateral summit in Moscow in July and include cutting their countries' nuclear arsenals to 1,500-1,675 operational warheads and delivery vehicles to 500-1,000.
START 1 obliges the countries to reduce nuclear warheads to 6,000 and their delivery vehicles to 1,600 each. In 2002, a follow-up agreement on strategic offensive arms reduction was concluded in Moscow. The document, known as the Moscow Treaty, envisioned cuts to 1,700-2,200 warheads by December 2012.