Russia [Images] and the United States on Monday signed a landmark agreement heralding bilateral cooperation in the field of civilian nuclear energy, including joint projects in other countries.

The 123 agreement between the two former Cold War rivals was signed in Moscow [Images] by the Russian Atomic Energy Corporation Rosatom chief Sergei Kiriyenko and US ambassador William Burns.

The civilian nuclear cooperation pact is a result of over 20 years of tough negotiations between the two countries and provides a legal framework for the nuclear trade between the companies of the two nations.

"The US and Russia were once nuclear rivals. Today we are nuclear partners with unique capabilities and unique responsibilities for global nuclear leadership," Burns said after signing the pact.

He added that the nuclear cooperation agreement is very significant for both the countries and will contribute to the development of civilian nuclear energy and will effectively check nuclear proliferation.

Rosatom chief Kiriyenko underscored the 'win-win' situation for Washington and Moscow created by the pact.

"Both sides find themselves in a win-win situation after signing this agreement, as huge opportunities open up for the companies of Russia and America, in cooperation on their national territories and third countries," Kiriyenko said after signing the agreement.

While the US will draw the advantage of highly developed Russian nuclear technology, the latter is set get a boost in its efforts to import and store spent fuel. Currently US controls majority of world's nuclear fuel.

At their St Petersburg [Images] summit in 2006, US President George W Bush [Images] and his Russian counterpart Vladimir Putin [Images] had agreed to speed up the signing of the 123 agreement on nuclear cooperation, which also paves ground for the supply of nuclear fuel to safeguarded nuclear reactors in the third countries, built by Russia and US.

The US also has similar agreements with other countries including China.