By Sarah Rainsford BBC correspondent in Moscow

US Defence Secretary Donald Rumsfeld is due to arrive in Moscow for talks with his Russian counterpart, Sergei Ivanov.

Donald Rumsfeld: Hoping to break deadlock

The flying visit is the latest in a long line of trips to Moscow by senior US officials anxious to forge an agreement on arms cuts.

With less than a month to go before President George W Bush meets Vladimir Putin in Russia, progress on the thorny issue has been slow.

Both sides have agreed to cut their nuclear arsenals by one third, but there is objection in Russia to the American proposal to store, rather than destroy, its decommissioned warheads - leaving them available for use in the event of a threat from the so-called rogue states.

The Russians say these "virtual cuts" are not good enough.

They are calling for "real and verifiable" reductions - to be policed by arms inspectors.

New relationship

The bumpy negotiation process is hardly surprising.

The proposed new treaty is being touted as the cornerstone of a new relationship of trust between the cold war enemies.

For the moment though, they are locked in intensive dialogue.

There is hope that Mr Rumsfeld's visit to Moscow can help move the discussion along, although the final chance to break the deadlock is likely to come next week, when Russian Foreign Minister Igor Ivanov travels to Washington.