U.S. President Barack Obama has signed ratification documents for a new nuclear disarmament treaty with Russia.
The new Strategic Arms Reductions Treaty (START) reduces commits the sides to reduce their stockpiles of deployed nuclear warheads to 1,550.
Russian President Dmitry Medvedev signed the agreement's ratification documents on January 26, after the two countries' lawmakers had earlier endorsed the pact.
The treaty will enter into force with an exchange of ratification documents by U.S. and Russian officials, expected during the February 4-6 Munich Security Conference.
compiled from agency reports