MOSCOW (Reuters) - Russia and the United States plan unprecedented cuts to their Cold War arsenals of nuclear weapons under a new arms reduction deal, Russian Foreign Minister Sergei Lavrov was quoted as saying on Tuesday.

Russia Foreign Minister Sergei Lavrov answers reporters questions at a news conference after his address to the U.N. Conference on Disarmament at the United Nations European headquarters in Geneva March 7, 2009. REUTERS/Denis Balibouse

The two largest nuclear powers have been trying to find a replacement for the 1991 Strategic Arms Reduction Treaty (START I), which led to the biggest reduction in nuclear weapons in history, but have so far failed to reach a deal.

“The treaty will stipulate a radical and unprecedented reduction in strategic offensive weapons,” Lavrov was quoted as saying by the state-owned RIA news agency.

Cutting the vast arsenals of nuclear weapons built during the Cold War is the centerpiece of U.S. President Barack Obama’s efforts to “reset” relations with Russia, which the United States is pressing to offer more help on Afghanistan and Iran.

Russia and the United States failed to agree on a successor to START I by December 5, when the treaty was due to expire, and have extended it as they search for a new agreement.

Obama and Russian President Dmitry Medvedev failed to clinch a deal when they met on the sidelines of the U.N. climate conference in Copenhagen last week. No reason was given, although they said they were close to an agreement.

Under a preliminary understanding agreed by the two presidents in July, the new treaty will reduce operationally deployed nuclear warheads to between at least 1,500 and 1,675, a cut of about one-third from current levels.

Lavrov, whose ministry is leading talks along with the U.S. State Department, said negotiations in Geneva would resolve remaining issues after the Christmas and New Year holidays.

“The delegations will resolve the remaining questions after the New Year break,” Lavrov was quoted as saying by RIA during on a visit to the Uzbek capital, Tashkent.

TECHNICAL ISSUES

The talks in Geneva have been held in secret and both sides have agreed to a news blackout, although tension spilled into the open last week when Lavrov accused U.S. negotiators of dragging their feet. This was denied by U.S. officials.

The negotiators have been discussing an array of technical arms control issues as they seek a deal which analysts say could pave the way for more ambitious talks aimed at cutting thousands of non-deployed nuclear warheads and shorter-range tactical nuclear warheads.

For a new START accord, Russia has called for cheaper verification procedures -- jargon for the inspections and data exchanges that ensure each side is implementing cuts.

Moscow has been concerned about a new generation of non-nuclear weapons with the destructive capability of some atomic weapons. Lavrov said on Tuesday the two types of weapon would be formally linked in a new treaty.

“The links between strategic offensive weapons with a nuclear and non-nuclear potential will be fixed in the new treaty,” Lavrov said, according to Interfax.