President Obama and Russian President Dmitry Medvedev sign the START Treaty Thursday. (PHOTO CREDIT: Getty Images)
Prague, Czech Republic (CNN) - U.S. President Barack Obama and Russian President Dmitry Medvedev on Thursday signed the START treaty, a major arms control agreement that reduces the nuclear stockpiles of both nations.
The treaty, whose full name is the Strategic Arms Reduction Treaty, builds on a previous agreement that expired in December.
The agreement cuts the number of nuclear weapons held by the United States and Russia by about a third.
"This day demonstrates the determination of the United States and Russia - the two nations that hold over 90 percent of the world's nuclear weapons - to pursue responsible global leadership," Obama said after the signing. "Together, we are keeping our commitments under the Nuclear Non-Proliferation Treaty, which must be the foundation for global non-proliferation."
Medvedev called START a "win-win situation" for the two countries.