US President Barack Obama: 'The US and Russia must lead by example'
US President Barack Obama and Russian President Dmitry Medvedev have reached an outline agreement to cut back their nations' stockpiles of nuclear weapons.
The "joint understanding" signed in Moscow would see reductions of deployed nuclear warheads to below 1,700 each within seven years of a new treaty.
The accord would replace the 1991 Start I treaty, which expires in December.
Mr Obama said the two countries were both "committed to leaving behind the suspicion and the rivalry of the past".
Separately, Russia also agreed to allow the US military to fly troops and weapons across its territory to Afghanistan, allowing it to avoid using supply routes through Pakistan that are attacked by militants.
The two countries also will set up a joint commission to co-operate over energy, and fighting terrorism and drug-trafficking. Military co-operation, suspended since last year's conflict between Russia and Georgia, will be resumed.
However, on the contentious issue of US plans to base parts of a missile defence shield in Eastern Europe, the presidents merely said they had agreed to a joint study into ballistic missile threats and the creation of a data exchange centre.
'Reversing the drift'
After three hours of talks at the Kremlin on Monday, Mr Obama and Mr Medvedev publicly signed a joint understanding to negotiate a new arms control treaty that would set lower levels of both nuclear warheads and delivery systems, including intercontinental ballistic missiles, submarine-launched missiles and bombers.
US-RUSSIA NUCLEAR DEAL
Each country to cut deployed nuclear warheads to 1,500-1,675 (currently 1,700-2,200)
Delivery systems to be within 500-1,000 range (currently 1,600)
Reductions so be achieved within seven years of new treaty
Treaty to be signed before Start I expires in December and include "effective" verification measures
"Within seven years after this treaty comes into force, and in future, the limits for strategic delivery systems should be within the range of 500-1,100 units and for warheads linked to them within the range of 1,500-1,675 units," the document said.
Under the 2002 Treaty of Moscow, each country is allowed between 1,700 and 2,200 deployed nuclear warheads and 1,600 delivery systems - meaning each side might only be required to decommission a further 25 warheads.
Correspondents also point out that the proposed cuts would still leave the US and Russia able to destroy each other many times over.
A White House statement said the new treaty would "include effective verification measures" and "enhance the security of both the US and Russia, as well as provide predictability and stability in strategic offensive forces".
BBC diplomatic correspondent Jonathan Marcus, in Moscow
By setting low expectations for this summit, the US and Russian leaders have been able to appear to achieve more than had been hoped.
The flurry of documents that has come out of this first day of discussions has been significant. President Obama sounded confident that a new strategic arms reduction treaty would be in place by the time the existing Start I agreement expires in December.
There is a new framework for military-to-military co-operation. There is an extensive document on joint action related to Afghanistan, not least a transit agreement allowing lethal US military equipment and supplies to transit Russia on its way to the front line.
The contentious issue of missile defence - where both leaders accepted there were still significant differences - was effectively "kicked into the long grass.
Afterwards, Mr Medvedev said the talks had been "very frank and very sincere", but that they had been, "without any doubt, the meeting we had been waiting for in Russia and the United States".
"I would like particularly to stress that our country would like to reach a level of co-operation with the United States that would really be worthy of the 21st Century, and which would ensure international peace and security," he said.
The Russian leader called Monday's agreement a "reasonable compromise", but cautioned that there remained "differences on many issues", most notably on the proposed US missile defence shield.
Mr Obama said he and Mr Medvedev were countering a "sense of drift" and were now resolved "to reset US-Russian relations so that we can co-operate more effectively in areas of common interest".
"We've taken important steps forward to increase nuclear security and to stop the spread of nuclear weapons," he said.
"This starts with the reduction of our own nuclear arsenal as the world's two leading nuclear powers the United States and Russia must lead by example, and that's what we're doing here today," he added.
The US president said he was confident a legally binding disarmament treaty would be signed by the end of the year, when Start I expires.
On Tuesday, Mr Obama will meet Prime Minister Vladimir Putin.
He said last week that he thought the former Russian president had "one foot in the old ways of doing business and one foot in the new".
"I think that it's important that even as we move forward with President Medvedev, that Putin understands that the old Cold War approaches to US-Russian relations is outdated, that it's time to move forward in a different direction," he told the Associated Press.
Mr Putin responded: "We stand solidly on our own two feet and always look into the future."
This summit is aimed at repairing strained US-Russian relations. Under the Bush Administration, ties between Washington and Moscow were considered almost as bad as during the Cold War.
The BBC's diplomatic correspondent Jonathan Marcus, in the Russian capital, says that while the two countries have not put aside all the suspicions of recent years, they are creating mechanisms to enable a much more positive relationship in the future.
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