The new single-warhead missiles will be based in the Saratov region about 700km south-east of Moscow.

The Russian Defence Minister, Igor Sergeyev, said they would keep intact Russia's nuclear potential for the foreseeable future.

"This is a very important event, because even in the difficult financial conditions of 1998 we have managed to find funds for financing this top priority area," Mr Sergeyev said.

Mr Sergeyev said that the adoption of the Topol-M system would preserve Russia's security and independence by keeping its missile and nuclear potential intact for the foreseeable future.

'Shield for 21st century'

The foundations for "Russia's missile and nuclear shield" for the 21st century are being laid today, the minister added.

Correspondents say the Topol-M could be the new heart of Russia's missile force. A futher 10 missiles are due to be commissioned within the next 12 months, and another 20 the following year.

The Topol-M is a long-range single warhead intercontinental ballistic missile, but it is lightweight and mobile, designed to be fired from a vehicle.

Its mobility means it is better protected than a silo-based missile from a pre-emptive first strike.

Deteriorating relations

The deployment comes at a time of deteriorating relations between Russia and the West. Moscow opposes the expansion of Nato membership into eastern Europe. It also opposes Nato action in the former Yugoslavia.

Last week, Russia accused the United States and the United Kingdom of flagrantly violating international law and endangering international security by bombing Iraq, in the face of Moscow's opposition on the United Nations Security Council.