MOSCOW -- Russian President Vladimir Putin, saying that relations with the United States have deteriorated into a "radically changed environment" of threat and instability, on Monday withdrew his country from a plutonium-disposal treaty that was one of the framework nuclear-disarmament deals of the early post-Cold War period.
The treaty on the disposal of plutonium, the material used in some nuclear weapons, was concluded in 2000.
It required Russia and the United States to destroy military stockpiles of plutonium, a deal presented as another encouraging step away from nuclear doomsday and an insurance policy against the materials falling into the hands of terrorists or rogue states.
The deal has no bearing on the numbers of nuclear weapons deployed by Russia or the United States. Instead, it concerns 34 tons of plutonium in storage in each country that might go into a future arsenal, none of which has yet undergone verifiable disposal.
The Kremlin had signaled previously that it planned to cut back on mutual efforts with the United States to secure nuclear material on Russian territory.
Times have changed, Putin wrote in the decree signed Monday.
"The threat to strategic stability posed by the hostile actions of the U.S. against Russia, and the inability of the U.S. to deliver on the obligation to dispose of excessive weapons plutonium under international treaties," forced Russia's hand, he wrote.
Josh Earnest, the White House press secretary, said the administration was disappointed by the Russian decision since "both leaders in Russia and the United States have made nonproliferation a priority."
"We've also been quite disappointed by a range of Russian decisions both in Syria and inside of Ukraine," Earnest said, adding that the decision on the plutonium deal was part of a problematic pattern.
Russia will withdraw from the original pact and subsequent amendments, Putin's decree says, meaning the country will no longer be treaty-bound to destroy its plutonium stockpiles. But the decree also offers an assurance, backed by no bilateral agreement, that the plutonium will not be used for military purposes.
"These agreements were designed to limit and circumscribe the future chances of getting back into a competition over nuclear arms," James Collins, an associate at the Carnegie Endowment for International Peace, said in a telephone interview. "It was an important step in defusing the strategic nuclear arms race."
Collins, who was the United States' ambassador to Russia when the agreement was signed, called the abrogation a "strange move," given the extraordinary danger, not least to Russians, should plutonium fall into terrorist hands. He added that it was "in my understanding the first time they have withdrawn from a specific nuclear agreement," highlighting the slide in relations lately.
Russia and the United States had reaffirmed the plutonium-disposal agreement in 2009, as President Barack Obama pursued the "reset" policy with Dmitry Medvedev, then the Russian president.
Russia had viewed the agreement as rendering disarmament irreversible by destroying the fissile materials accumulated during the Cold War. In this light, the Russians had interpreted the treaty as requiring that the plutonium be irreversibly transformed into nonexplosive materials by using it in civilian nuclear power plants as mixed oxide fuel. Russia is pressing ahead with that.
But glitches and cost overruns in the mixed oxide fuel plant at Savannah River, S.C., delayed the U.S. program. This year, Obama proposed canceling the program in the 2017 budget and instead sending the plutonium for long-term storage at a nuclear waste site in Carlsbad, N.M.
The State Department has said the move complies with the treaty, but the Russians have said it does not, as Putin reaffirmed on Monday.
As ties with the West have frayed under Putin, analysts in Moscow have floated the prospect of a Russian pullback from an array of disarmament agreements dating from a period of greater friendliness. Two years ago, for example, the Obama administration accused Russia of violating another bedrock security agreement by testing a prohibited ground-launched cruise missile.
In order to resume cooperation on plutonium, the Kremlin first wants the removal of all economic sanctions and compensation for the damage they have caused; the repeal of the Magnitsky Act, which allows Americans to freeze the assets of Russian officials thought to have been involved with human-rights violations; and reductions in the U.S. military presence in countries that joined NATO after Sept. 1, 2000.
A Section on 10/04/2016