MOSCOW, May 15 (Xinhua) -- Russia and the United States will hold the first round of full-format talks on a new strategic arms reduction treaty on May 19-21 in Moscow, a source with the Russian Foreign Ministry said on Friday.

    "The upcoming negotiations will not be just an exchange of opinions, but a transition to substantive discussion of the future treaty, with the parties putting forward particular proposals," the diplomat was quoted as saying by the Interfax news agency.

    The U.S. delegation will be led by U.S. Assistant Secretary of State Rose Gottemoeller, and the Russian side will be headed by Anatoly Antonov, director of the security and disarmament department of the Russian Foreign Ministry, the source said.

    The Strategic Arms Reductions Treaty (START), which places a limit of 6,000 strategic or long-range nuclear warheads on each side, is due to expire this December.

    Russian President Dmitry Medvedev and U.S. President Barack Obama, at their first meeting on the sidelines of the G20 summit in London, agreed to negotiate a replacement for START by the end of the year.