Russia on Thursday welcomed a US proposal on replacing a key nuclear disarmament treaty, saying it could help clinch a deal before the treaty expires next month, the foreign ministry said.

The latest US proposal in negotiations on renewing the landmark 1991 Strategic Arms Reduction Treaty (START) was "constructive," foreign ministry spokesman Andrei Nesterenko said.

"We hope the constructive proposal that US National Security Adviser James Jones made in Moscow last week will let us bring our positions together and arrive at a balanced document," Nesterenko told the Interfax news agency.

START expires on December 5 and the eighth round in marathon US-Russian negotiations on replacing it will kick off on Monday in Geneva.

"We hope that this will be the last round and that by December 5 we will have agreed a new accord," Nesterenko said.

"Both sides are aware of the responsibility they have shouldered and are doing everything to achieve the necessary results. There is progress."

Talks on a successor treaty hit a dead end under former US president George W. Bush, dogged by US plans to deploy a missile shield in ex-communist states in eastern Europe, a project that rankled with Russia.

But negotiations gained speed after President Barack Obama scrapped the shield plans in September and pledged to intensify work with Moscow amid a broader effort to "reset" strained US-Russian ties.

Last week the Kremlin's top foreign policy advisor Sergei Prikhodko said "serious progress" had been made in the START negotiations since the last round in October.

But Nesterenko warned Thursday that a number of stumbling blocs remained and he would not cheer a new accord until "every last comma" had been agreed.

"We have a saying in negotiations: 'Nothing is agreed until everything is'. So until we have agreed every last comma, any attempt to assess how far we have come may be deceptive."

A major issue hampering progress in negotiations is Moscow's insistence that the new deal impose deep cuts in the number of carriers capable of delivering nuclear warheads.

"Lower limits must be set on the number of strategic carriers, including ground-based intercontinental ballistic missiles (ICBM), submarine launched ballistic missiles (SLBM) and heavy bombers," Nesterenko underlined.

Moscow has also fought for wording that would link US missile defence plans with the disarmament regime.

Nesterenko emphasised the linkage between offensive and defensive weapons in negotiations was "extremely important since it will make up for the absence of an agreement on missile defence shield."

He also reiterated Russia's complaint that current arms inspections are expensive and a hassle, asking that controls be relaxed in the new treaty.

START, signed in 1991 just before the break-up of the Soviet Union, is seen as a cornerstone of strategic arms control, setting limits on the number of nuclear warheads for the two former Cold War superpowers.

At a Moscow summit in July, Obama and his Russian counterpart Dmitry Medvedev agreed to each reduce their nuclear arsenal to between 1,500 and 1,675 warheads within seven years.

They also agreed cuts on the number of ballistic missile carriers to between 500 and 1,100.