U.S. and Russian arms negotiators met Tuesday for a third round of talks on replacing the landmark 1991 Strategic Arms Reduction Treaty.
The two-day talks, in Geneva, are the last scheduled negotiations before a summit in July between U.S. President Barack Obama and his Russian counterpart, Dmitri Medvedev.
The two leaders agreed earlier this year to open talks on a new agreement to replace the treaty when it expires on December 5.
President Medvedev has said Russia is willing to make deeper cuts in its nuclear arsenal, but only if the United States addresses Russian concerns over U.S. plans for a missile defense system in central Europe.
A U.S. State Department spokesman, Ian Kelly, Monday reaffirmed that the United States sees no link between the proposed missile-defense system and the size of each side's strategic nuclear arsenal.
The proposed U.S. missile plan would place 10 missile interceptors in Poland and guidance radar in the Czech Republic.
U.S. officials have said repeatedly that the system is not intended for any use against Russia. However, Russian President Medvedev and his predecessor, Vladimir Putin, have threatened to deploy short-range Russian missiles near European Union borders if Washington goes forward with the plan.
President Obama has not yet announced whether his administration will go ahead with the missile defense shield. U.S. officials have said Mr. Obama's decision likely will depend on an assessment of the threat level by the United States and its allies.
Some information for this report was provided by AFP.