MOSCOW -- Russia and the United States have signed a key agreement on civilian nuclear power that will give Washington access to Moscow's nuclear technology and potentially hand Russia lucrative deals on storing spent nuclear fuel.

U.S. Ambassador William Burns and Russia's top nuclear official, Sergei Kiriyenko, have signed the deal the day before Dmitry Medvedev succeeds Vladimir Putin as president.

Cooperation on nuclear issues between Russia and the United States had cooled in recent years because of disagreements over how to handle Iran's perceived nuclear threat.

The new agreement signed today will formally allow nuclear deals between U.S. and Russian companies. The United States has similar agreements with other major economic powers, including China.