The New START (Strategic Arms Reduction Treaty) is a nuclear arms reduction treaty between the United States of America and the Russian Federation with the formal name of Measures for the Further Reduction and Limitation of Strategic Offensive Arms. It was signed on 8 April 2010 in Prague, and, after ratification, entered into force on 5 February 2011. It is expected to last at least until 2021. New START replaced the Treaty of Moscow (SORT), which was due to expire in December 2012. In terms of name, it is a follow-up to the START I treaty, which expired in December 2009.