MOSCOW - Russian President Dmitry Medvedev has ratified a Russian-US agreement on the disposal of excess weapon-grade plutonium, the Kremlin press service said on Tuesday.

According to local media reports, Russia intends to spend up to $3.5 billion on the program, which was seen as a continuation of the new Russian-US strategic arms reduction treaty (START) that slashes arsenals of each country to 1,550 strategic warheads.

The reports also said the United States is expected to spend some $400 million on the program.

Russian Foreign Minister Sergei Lavrov and US Secretary of State Hillary Clinton signed in April 2010 a final agreement on eliminating excess weapon-grade plutonium from defense programs.

Under the agreement, the two sides will each dispose of 34 metric tons of excess plutonium, which is enough to create several thousand nuclear weapons. The program is to be launched before 2018.

The agreement was passed by the Russian State Duma, or lower house of the parliament, on May 20 and upheld by the Russian Federation Council, the upper house, on May 25, 2011.