Russian President Vladimir Putin yesterday ordered a halt to an agreement with the United States on plutonium disposal, citing Washington's "unfriendly actions".
The deal, signed in 2000, was meant to allow both nuclear powers to dispose of weapons-grade plutonium from their defence programmes, a move seen as a key step in the disarmament process.
The two countries recommitted to the deal in 2010. The Kremlin indicated yesterday that it would stick to the agreement if Washington lifts sanctions and ends other policies seen as unfriendly to Moscow.
Putin charged earlier this year that the United States was not honouring the deal by disposing of plutonium in a way that allowed it to retain its defence capabilities.
The suspension is symbolic of the breakdown in nuclear nonproliferation cooperation, an expert said.
The decree published yesterday states that Russia is pulling out of the agreement "due to a drastic change in circumstances, the appearance of a threat to strategic stability due to unfriendly actions of the United States toward Russia".
It claimed that Washington was "unable" to carry out the terms of the agreement and that Moscow "must take urgent measures to defend Russian security".
Putin's spokesman Dmitry Peskov told journalists that Washington has not honoured the agreement and "Russia no longer thinks it possible to carry out the conditions of the agreement alone" due to "general tension" between the two countries.
"It's a symbolic gesture that demonstrates that the sides no longer cooperate in this sphere," said independent military expert Alexander Golts, adding that it was not the first agreement to be suspended in the non-proliferation sphere.
A bill submitted by Putin to parliament, which asked lawmakers to support the agreement's suspension, indicated that some quid pro quo could still keep the deal alive.