Russia and US 'to reset relations' with nuclear weapon deal

In a statement after a meeting in London, the pair said they had ordered negotiators to report first results on a fresh arms treaty by July, when Mr Obama will visit Moscow for a summit.

"In the past years, there were strains in relations between our two countries and they were drifting in the wrong direction," Russian president Mr Medvedev said.

"This was not in the interests of the United States, Russia or global stability. We agreed to open a new page in these relations, to reset them, given the joint responsibilities of our states for the situation in the world."

Mr Obama said he and Mr Medvedev had begun "constructive dialogue" on issues from nuclear proliferation to counter-terrorism to economic stability. They stressed that a new nuclear arms deal needed to be in place before the 1991 Strategic Arms Reduction Treaty expires on 5 December.

The leaders, both in their forties, acknowledged lingering differences over last year's Russia-Georgia war and over American proposals to base parts of a missile shield in Eastern Europe, something Moscow considers a threat to its security.

Those disagreements have badly damaged relations, but the two countries have vowed to "press the reset button" on ties - an aim the planned arms treaty could help them to achieve. The joint statement said: "The new agreement will mutually enhance the security of the parties and predictability and stability in strategic offensive forces.

"We are ready to move beyond Cold War mentalities and chart a fresh start in relations between our two countries."

Earlier today Mr Obama declared that the two countries should tackle "the greatest threat to humanity" by ushering in a new era of nuclear disarmament.

Ahead of his first meeting with Mr Medvedev, Mr Obama said the two biggest nuclear powers should "lead by example" in slashing weapons stockpiles. He said it was in Washington and Moscow's interests to agree a new long-range missile treaty to cut their nuclear arsenals and prevent weapons falling into the hands of terrorists.

In what was billed as an event with potentially greater significance even than the G20, the two leaders talked about everything from missile defence to Iran and Afghanistan.

Mr Obama stressed that he did not want to "paper over" the differences between Russia and the US, but said there was a "broad set of common interests". He said the spectre of nuclear weapons in the hands of terrorists "continued to be the greatest threat against humanity".

The Obama administration and the Kremlin now have less than nine months to write Start's successor.

Six senior American and Russian security experts - including the former commander-in-chief of the US Atlantic Command and a former Russian foreign minister - followed Mr Obama's call and said scrapping warheads was the new "realpolitik".

The Global Zero group of foreign policy experts urged Mr Obama and Mr Medvedev to move beyond traditional arms control and set the world on a course towards total elimination of all nuclear weapons.