Russia and the United States should speed up ratification of the new START arms control treaty, Russian Foreign Minister Sergei Lavrov and his US counterpart Hillary Clinton agreed late Tuesday.

"Both sides voiced the desire to finish the ratification process as soon as possible," after telephone talks, a Russian foreign ministry statement said.

Obama and his Russian counterpart Dmitry Medvedev signed the new arms reduction deal in an elaborate ceremony in Prague in April.

But the treaty must be ratified by the Senate, where it faces opposition from the Republican party whose lawmakers voiced fears that the agreement could undermine US plans for missile defence.

Russia has said it reserves the right to withdraw from the treaty if Washington presses ahead with missile defence systems in a way that Moscow opposes.

The START treaty would significantly cut US and Russian nuclear weapons to about 1,550 each.

That figure represents a 74 percent reduction from the arsenal size agreed in the original START deal, signed in 1991, which expired at the end of 2009.