Photo: RIA Novosti

US National Security Advisor Thomas Donilon will visit Russia, said Russia’s Itar Tass today. Donilon carries a letter proposing strategic weapons reductions and missile defense cooperation to Russian Prime Minister Vladimir Putin. In 2010, Russia and the US signed a Strategic Arms Reduction Treaty, Start-3, which took effect in February, 2011. Start-3 constrains each side to reduce its nuclear warheads to 1,550 units.