During a news conference, broadcast live on the Internet, Colonel-General Vladimir Yakovlev said the Russian missile command system was safe and support systems had been successfully tested for Y2K problems.

The so-called millennium bug is caused by older computer software that records dates using only the last two digits of a year. This means 2000 could be interpreted as 1900, causing potential crashes or malfunctions when the year rolls over.

Russia 'has concluded' its computer tests

The assurance came a day after a Russian magazine reported buying access to top-secret documents indicating the "horrifying" danger of Russian Strategic Missile Troops (SMT) computer failure at the millennium.

The Russian weekly Argumenty I Fakty acknowledged that the documents might not be genuine.

Nevertheless, the magazine concluded that doubts still lingered.

'Impossible to copy and impregnable'

General Yakovlev said he could guarantee that Russia's missiles would not be launched accidentally "because today the command system which exists for the intercontinental ballistic missiles of the Russian Federation is impossible to copy and impregnable for any kind of intrusion into its algorithm".

The support systems had also been tested for Y2K problems, the general said, and added: "This programme was finished with autonomous tests and a series of tests on 1 December.

"Today we have no doubt that the supply systems will carry out their functions as well."

Close co-operation

Russia and the United States are collaborating closely on eliminating possible millennium bug related problems in the nuclear industry and the defence system.

Russian and US experts will sit side by side at a base in Colorado over the New Year period to ensure there are no nuclear mishaps.

Today the command system... is impossible to copy and impregnable for any kind of intrusion into its algorithm.

General Yakovlev

Eighteen Russian defence specialists will fly to Colorado on 23 December. They will start a joint watch with their US colleagues on 27 December.

They will work 24 hours a day for three weeks at Peterson Air Force Base, headquarters of the US missile-tracking Space Command.

"This sharing will reduce the chance that a turn-of-the-millennium computer error will create an end-of-the-year security incident," US Defence Secretary William Cohen said when the programme was announced.

Linking nuclear industries

At the beginning of December, the two countries unveiled a high-tech video and telecommunications link to monitor possible problems in their 132 nuclear reactors during the Y2K roll-over.

The White House in Washington has its own Y2K crisis centre

Announcing the plans, US Energy Secretary Bill Richardson said linking the two countries' atomic command centres would help prevent mishaps with the coming of the new millennium.

"While we don't expect any major problems, there may be glitches. We have to be ready on both sides," he told a press briefing at the top-secret Situation Crisis Center in Energy Department headquarters. The centre provides communications with energy facilities across the US.

Mr Richardson said the two countries' experts would sit alongside each other in the joint command centres in case there were any emergencies.

'Top secret' documents

All 103 of America's commercial reactors were recently cleared as being ready to deal with the change.

In its 7 December issue, Argumenty I Fakty carries an article by its military observer, Aleksandr Kondrashov.

This sharing will reduce the chance that a turn-of-the-millennium computer error will create an end-of-the-year security incident.

William Cohen

He says he was shown "top secret documents" talking of President Boris Yeltsin's "nuclear suitcase failing, obsolete computer systems, neglect and collapse at strategic command points where ceilings which have not been repaired for ages are now falling in and of cables and wires having been gnawed away by rats."

Argumenty I Fakty says, it was offered the documents for $50,000 by a specialist on missile system safety who was recently released into the reserves.

Worries over Russian spending

But the magazine concedes that the documents could be exaggerating or could even be a skilful fabrication.

The United States has said on several occasions it was worried Russia had not carried out sufficient security checks on its strategic missiles and nuclear power plants.

The Russian military has had less than $4m to fix Y2K problems - many Western businesses have been spending more.

The Pentagon is spending $3.8bn in making its computers Y2K ready.