The United States and Russia are successfully implementing their nuclear disarmament agreements and are continuing to work on the next steps in this direction, a U.S. Department of State official said on Tuesday.

Rose Gottemoeller, the Assistant Secretary, Bureau of Arms Control, Verification and Compliance said addressing the Conference on Disarmament in Geneva that last year “the U.S.-Russian Plutonium Management and Disposition Agreement (PMDA) and its Protocols came into force.”

“The PMDA commits the United States and the Russian Federation each to dispose of no less than 34 metric tons of excess weapon-grade plutonium - enough material in total for approximately 17,000 nuclear weapons,” she added.

The New START document, signed by the Russian and U.S. presidents in 2010, cuts both countries’ strategic nuclear arsenals to a maximum of 1,550 warheads, down from the previous ceiling of 2,200.

“The New START Treaty entered into force on February 5, 2011. Implementation is going well and continues to contribute positively to the U.S.-Russian relationship,” she said.

“The treaty represents a strong foundation for further bilateral reductions and an important step on the path towards a world without nuclear weapons. Discussions between our two governments on the next steps are underway,” Gottemoeller said.

Relations between Moscow and Washington have been tense recently over the United States continuing its build-up of missile defense systems in Europe, which Russia sees as a direct threat to its national security.

Last November, Russian President Dmitry Medvedev warned that Russia would deploy missiles and may opt out of the New START nuclear reductions agreement if Russia, the United States and NATO failed to find a way to work together on European missile defenses.

Earlier this month, Under Secretary of State for Arms Control Ellen Tauscher said, however, that the administration of President Barack Obama would not give Russia any legally binding guarantees that U.S. missile defenses in Europe will not impact Russia’s strategic deterrent.