Russia's Putin orders plutonium cleanup programme with U.S. to be suspended

A Russian Yars RS-24 intercontinental ballistic missile system drives during the Victory Day parade, marking the 71st anniversary of the victory over Nazi Germany in World War Two, at Red Square in Moscow, Russia, May 9, 2016. REUTERS/Grigory Dukor

MOSCOW (Reuters) - Russian President Vladimir Putin on Monday suspended a treaty with Washington on cleaning up weapons-grade plutonium, signalling he is willing to use nuclear disarmament as a new bargaining chip in disputes with the United States over Ukraine and Syria.

Starting in the last years of the Cold War, Russia and the United States signed a series of accords to reduce the size of their nuclear arsenals, agreements that have so far survived intact despite a souring of U.S.-Russian relations under Putin.