In the past, Washington has refused to explicitly recognize North Korea as a nuclear-armed state, though the Stalinist state is estimated to have enough plutonium to build several nuclear weapons.
Medvedev and U.S. President Barack Obama last week approved the final terms of the Strategic Arms Reduction Treaty's successor, which would require the United States and Russia to both lower their respective strategic arsenals to 1,550 deployed warheads. Each nation's fielded nuclear delivery vehicles would be capped at 700, with another 100 allowed in reserve.
Washington and other Western powers in the six-nation group have courted Moscow and Beijing for endorsement of a new round of Security Council sanctions, which would seek to end Iranian atomic activities that could support nuclear weapons development.