The next round of Russian- U.S. consultations on a replacement for the Strategic Arms Reduction Treaty (START 1) will be held on Monday in Geneva.

START 1, signed in 1991 and due to expire on December 5, is the bilateral basis for Moscow and Washington''s nuclear disarmament.

Russian President Dmitry Medvedev said in an interview ahead of a visit to Serbia this week that Russia was doing its utmost to agree on a new treaty.

"We are doing everything necessary to achieve the signing of a relevant document by December," he told Serbia''s Vecernje Novosti.

Medvedev and his U.S. counterpart Barack Obama agreed in July in Moscow on the outline of a deal to replace START 1, including cutting their countries'' nuclear arsenals to 1,500-1,675 operational warheads and delivery vehicles to 500-1,000.

The drafting of the new pact was one of the key themes of talks held in Moscow during last week''s visit of U.S. Secretary of State Hillary Clinton, and the negotiating teams worked on specific language during meetings in Geneva earlier this month.

The Russian delegation is headed by Anatoly Antonov, director of the Foreign Ministry''s Department of Security and Disarmament, while the U.S. team of negotiators is led by Assistant Secretary of State Rose Gottemoeller.