President Barack Obama and his Russian counterpart Dmitry Medvedev have signed a landmark nuclear arms reduction treaty.
Analysts say the new Start treaty heralds a new era in US-Russian relations, and will promote greater cooperation in tackling nuclear threats elsewhere.
There were smiles all round as months of negotiations paid off.
It comes a year after Barack Obama called for a move towards worldwide nuclear disarmament at the EU-US summit in Prague last April.
“The new Start Treaty is an important step forward, it is just one step on a longer journey. As I said last year in Prague this Treaty was to set the stage for further cuts, and going forward we hope to pursue discussions with Russia on reducing both our strategic and tactical weapons including non deployed weapons,” said US President Barack Obama.
Russia and the US control 90 percent of the world’s nuclear weapons.
By signing the treaty, the former Cold War foes have pledged to reduce stockpiles of nuclear warheads by around thirty percent.
That means cutting the number of their most deadly long range nuclear weapons from a ceiling of 2,200 to around fifteen hundred.
It replaces the 1991 Strategic Arms Reduction Treaty which expired last December.
Obama had some tough words for Teheran, warning that failure to comply with the Nuclear Non-Proliferation Treaty and risking an arms race in a volatile region would not be tolerated.
Russia meanwhile hinted at possible support for tougher measures against Iran.
“Unfortunately, Teheran continues to ignore all constructive compromises which have been proposed. And we can not close our eyes to that. I can not rule out that the UN Security Council will not revisit the question of sanctions.”
The signing of the treaty marks a dramatic improvement in US-Russian relations, which reached breaking point eighteen months ago after the Georgian war.
The two countries also fell out over US plans for a missile defence shield based in Poland and the Czech Republic.