(USA TODAY) -- Russian President Vladimir Putin suspended a deal with the United States on Monday on the disposal of weapons-grade plutonium because of "unfriendly" acts by Washington.
In a decree, Putin accused the U.S. of creating "a threat to strategic stability" and Russia said the U.S. failed "to ensure the implementation of its obligations to utilize surplus weapons-grade plutonium," Reuters reported.
The two countries are currently at odds over the Ukraine, where Russia annexed Crimea in 2014, and the five-year conflict in Syria, according to Reuters.
Putin said in the decree that Russia had to take "urgent measures to defend the security of the Russian Federation," the BBC reported.
Under the 2000 agreement, the U.S. and Russia is expected to get rid of 34 metric tons of plutonium by burning it in reactors, according to the BBC. The deal came into effect in 2010 and was signed by Russian Foreign Minister Sergei Lavrov and then-Secretary of State Hillary Clinton.
"For quite a long time, Russia had been implementing it (the agreement) unilaterally," Kremlin spokesman Dmitry Peskov said Monday.
"Now, taking into account this tension (in relations) in general ... the Russian side considers it impossible for the current state of things to last any longer," Preskov said, according to Reuters.
Viewed as a major non-proliferation effort, the plutonium agreement was expected to take at least two decades and cover only a fraction of the weapons-grade plutonium both countries possess. The U.S. is believed to have about 100 metric tons of weapons-grade plutonium and Russia about 140 metric tons, the Associated Press reported.