Russian Foreign Minister Sergei Lavrov has expressed optimism that the United States and his country will negotiate a new treaty on nuclear arms, to replace one set to expire in December.

Lavrov spoke to Russian reporters Tuesday during a return flight from meetings in Washington with top U.S. officials.  The meetings included talks on renewing the 1991 Strategic Arms Reduction Treaty, known as START. 

Lavrov said Moscow wants the new treaty to cover all nuclear-capable bombers and missiles, as well as warheads in storage.

President Barack Obama and his Russian counterpart, Dmitri Medvedev, agreed at a London summit earlier this year to resume negotiations, following a months-long diplomatic rift sparked by Russia's 2008 invasion of Georgia.

U.S. and Russian negotiators are scheduled to open talks on the new treaty May 18 in Moscow.

Presidents Obama and Medvedev are expected to discuss the new treaty at a summit in Russia in July.

Some information for this report was provided by AFP and AP.