Moscow - Hailing a "fresh start" in relations, US President Barack Obama and his Russian counterpart Dmitry Medvedev reached basic agreement Monday that there must be a follow-up treaty to the START disarmament pact due to expire at the end of the year. White House officials said Obama and Medvedev signed a "joint understanding" which aims to reduce the number of nuclear warheads held by each to between 1,500 and 1,675, compared with the current START (Strategic Arms Reduction Treaty) maximum of 2,200.
They would also aim to reduce the number of rockets capable of delivering the warheads from the current maximum of 1,600 allowed for each side to between 500 and 1,100.
There was agreement that the groundwork had to be laid for a new treaty limiting nuclear arms and preventing their use in terrorist attacks, and the two sides would increase cooperation towards this during the coming months.
At a press conference following their talks, Medvedev said Moscow was seeking a "fresh start" in relations with Washington, despite their continuing differences.
"Our countries are aiming at cooperation commensurate with the 21st century," he said. Agreeing to forge ahead with disarmament talks, he said, showed that Russia and the United States were facing up to their superpower responsibilities.
Obama for his part praised what he called Russia's contribution in stemming nuclear threats to the world, and he and Medvedev had managed to initiate a fresh start in relations between the two sides.
He stressed the joint efforts being made towards a follow-up to the START pact, and said the United States and Russia aimed to "lead by example" in cutting back their nuclear weapons.
The two presidents also signed an agreement allowing the US military to fly over Russian territory with supplies and materials en route to Afghanistan.
Both sides stressed the need to stabilize Afghanistan, as although Russia has no military involvement there, the Kremlin fears an upswing in tension along its southern flank.
Talks on the controversial missile defence system in eastern Europe that the US had planned were to continue. The previous Bush administration had planned to install a missile defence system - ostensibly against an Iranian threat - in Poland and the Czech Republic.
Russia strongly opposed the plan, and had linked a nuclear disarmament deal to progress on the eastern Europe missile defence issue.
Progress was made on Monday, with the sides agreeing to cooperate on dealing with third-party missile threats.
Russian officials said that they had called on their experts to investigate the threats posed by ballistic weapons, and agreed on the establishment of a centre to exchange information on such threats between Russia and the US.
Heading into the summit Monday, Obama and Medvedev stressed their similarities and tried to downplay former disputes.
"The United States and Russia have more in common than they have differences," said Obama in comments carried by the Itar-Tass news agency. "If we work hard in these next few days we can make extraordinary progress that would benefit the people of both countries."
Medvedev sounded a similar note.
"We hope that as a result of our today's work, tomorrow's work and full-scale bilateral communication, we will close a number of complicated pages in the history of Russian-American relations and will open a new page," he said.
Both presidents have also expressed a desire to improve relations, which have been strained of late, over Russia's war with Georgia in the summer of 2008, and a prospective US plan to station a missile defence system in eastern Europe.
The president's plane, Air Force One, touched down amid rain at the Russian government's airbase at Vnukovo on Monday morning.
On Monday Russian newspapers however expressed scepticism over whether the meeting signified a new start - or "reset" - in relations between the two states.
Sticking points include disagreements over Russia's membership of the World Trade Organization, the status of the Georgian breakaway republics of South Ossetia and Abkhazia, the prosecution of Russian oil billionaire Mikhail Khordokovsky and other issues.
Russia has also been the only Group of Eight country to acknowledge Iranian President Mahmoud Ahmadinejad as the clear victor in the disputed June 12 presidential election.
Obama is to meet with Prime Minister Vladimir Putin on Tuesday, as well as representatives of Russian human-rights organizations. Obama has been accompanied on his trip by his wife Michelle and their two daughters.
Obama is then to fly to Italy where he will attend the annual G8 summit in L'Aquila. The summit agenda includes the global recession, climate change and the situations in Iran and the Middle East.
The G8 summit comes ahead of the larger Group of 20 planning to meet in September in the US city of Pittsburgh, Pennsylvania, to discuss the economic crisis. Obama has been at odds with his European counterparts, who want to see more regulation of US financial markets.
In Ghana, Obama plans to outline his Africa policy in a speech during his first visit as president to the continent. Obama has in years past visited Kenya, the homeland of his late father.
