The cheer over Russia's approval of a new nuclear disarmament treaty is short-lived as it masks Moscow's reluctance to ensure further cuts, threatening US President Barack Obama's vision of a nuclear-free world.

Russia is going through the final motions of ratifying a new START treaty that reduces old nuclear warhead ceilings by 30 percent and limits each side to 700 deployed long-range missiles and heavy bombers.

The pact will be submitted for a last vote to Russia's lower house of parliament on January 25 and almost certainly be ratified by the upper chamber the following day.

It was backed by the US Senate last month.

But analysts said that Moscow and Washington have little time to rejoice having put in motion the first round of mandated nuclear weapons reductions since the Cold War.

Obama, who pledged to "reset" Russia-US relations, sees START as only a stepping stone to further cutbacks, but a top Russian official made clear last week that the president's insistence for another round of negotiations later this year was not being received well in Moscow.

"I am convinced that before talking about any further steps in the sphere of nuclear disarmament ... it is necessary to fulfill the new START agreement," Foreign Minister Sergei Lavrov told reporters.

Only "then will be it be clear what additional steps should be taken to strengthen global security," he added.

In Russia's view, the round of disarmament which covers short-range tactical missiles dear to Moscow, balances out the West's current dominance in modern conventional forces.

The US Bulletin of the Atomic Scientists estimates that Russia has 2,050 deployed tactical warheads that could be deployed in small nuclear campaigns in its periphery. The United States has just 500.

Lavrov said Russia's commitment under the new START treaty will not be "fulfilled" for another seven years, and some analysts interpreted the comments as a flat-out rejection of Obama's latest overture.

"It seems Lavrov meant that these talks will not start for another seven years," said independent military commentator Alexander Golts.

"It is also important to note that Lavrov said these talks should be tied to space and conventional weapons," said Golts.

"This is basically a polite way of saying that we are not ready to talk about it."

The Russian foreign minister Lavrov spelled out a series of amendments that appear inherently unacceptable to the United States.

They include the prohibition of military space programmes that the Pentagon is currently studying and a requirement for all talks to include conventional warheads that the West is developing much faster than Russia.

Lavrov even suggested that the next round of talks should for the first time involve other countries -- presumably China and other emerging nuclear powers that may press their own demands on Washington.

"Most Russian experts see nuclear weapons as an equalizer," said Moscow's Centre for Disarmament Director Anatoly Dyakov.

"They believe that the removal of nuclear weapons must be accompanied by a full transformation of international relations that ensures that no country can suddenly decide to use force."

Military analysts estimate that it will take Russia another decade to develop a conventional weapons programme capable of re-establishing some semblance of parity with the West.

But they warned that it is highly unlikely that Russia will be able to delay the next round of nuclear negotiations for as long as suggested by Lavrov.

"We are going to have to start these whether we like it or not," said Institute for Strategic Assessment head Alexander Konovalov.

"The Americans will not stand for this kind of disparity."