Russia said on Wednesday it was suspending its nuclear and energy research agreement with the United States as a countermeasure against Washington for imposing sanctions on Russia over Ukraine.
The government also said it was terminating for the same reasons an agreement between its nuclear corporation Rosatom and the U.S. Department of Energy on feasibility studies into conversion of Russian research reactors to low enriched uranium.
On Monday, President Vladimir Putin suspended a treaty with Washington on cleaning up weapons-grade plutonium, signaling he is willing to use nuclear disarmament as a new bargaining chip in disputes with the United States over Ukraine and Syria.
"The regular renewal of sanctions against Russia, which include the suspension of Russian-American cooperation in the field of nuclear energy demands the adoption of countermeasures against the U.S. side," the Russian government said on its website.
The agreement on co-operation in nuclear- and energy-related scientific research, signed in 2013, provided the legal framework necessary to expand work between U.S. and Russian nuclear research laboratories and institutes in nuclear technology and nonproliferation, among others.
The uranium agreement, signed in 2010, provided for feasibility studies into the conversion of six Russian research reactors from dangerous highly enriched uranium to more secure low enriched uranium.
The West imposed economic sanctions on Russia over its annexation of Ukraine's Crimea peninsula in 2014, followed by a pro-Russian insurrection in the east of the country. The breakdown of a ceasefire in Syria, where Russia backs government forces and the West supports rebel groups, has added to tensions.