The United States and Russia will begin talks Thursday on finding a successor deal to the 1991 Strategic Arms Reduction Treaty that significantly cut American and Russian nuclear arsenals, an official said. The talks will take place in the US and Russian diplomatic missions in Geneva, a US. official said Wednesday. They will last until Nov. 21. The START treaty signed by Soviet President Mikhail S. Gorbachev and US President George H.W. Bush reduced nuclear warheads to about 6,000 apiece - cutting each country's arsenal by at least a quarter. The accord expires on Dec. 5, 2009.