MOSCOW (Reuters) - Russian President Dmitry Medvedev said on Sunday that a deal with the United States on a landmark nuclear arms reduction treaty was 95 percent agreed, news agencies reported on Sunday.

Everything in negotiations is going fine, 95 percent of the new deal's issues have been agreed upon, Interfax quoted him as telling reporters in the Black Sea town of Sochi.

Medvedev's spokeswoman Natalya Timakova declined comment.

President Barack Obama and Medvedev laid out plans last year to forge a successor to the Strategic Arms Reduction Treaty, called START, and reduce the arsenals of the two largest nuclear powers.

It is an important element of efforts to mend relations between Washington and Moscow, which plunged to post-Cold War lows after Russia's brief war with pro-Western Georgia in 2008.

Negotiators were unable to reach agreement by December 5, when START I expired, and official negotiations in Geneva have not resumed after a break over the holiday period.

A top U.S. official indicated earlier this month that they would resume on January 25, and Russia's Foreign Minister Sergei Lavrov said on Friday he expected an agreement would be reached soon once negotiations resume at the beginning of February.

Any agreement must be ratified by lawmakers in both countries to take effect.

In July, Obama and Medvedev agreed that the new treaty should cut the number of nuclear warheads on each side to between 1,500 and 1,675, and the number of delivery vehicles to between 500 and 1,100.

(Reporting by Amie Ferris-Rotman and Denis Dyomkin; Editing by Elizabeth Fullerton)

Russia Dmitry Medvedev Barack obama