As part of a raft of measures, American experts will conduct Y2K bug tests to try to protect Russia's nuclear industry from a potential disaster in the new millennium.

The package also includes a new crisis centre at the Russian Nuclear Power Ministry, which was unveiled at the signing by US Secretary of Energy, Bill Richardson, and his Russian counterpart, Yevgeny Adamov.

The BBC's Juliet Hindell reports from Tokyo: "A little late to tackle the millennium threat"

Both men said the nuclear accident in Japan on Thursday demonstrated how useful co-operation could be.

American technicians will go to Russia in November to ensure that key facilities, including reactors at nuclear power plants and the national electricity grid, will be ready for the new millennium.

Russia is widely perceived as being one of the countries least prepared for Y2K computer failures.

The 'millennium bug' will cause many devices to reset their internal clocks to the year 1900, rather than 2000, on 1 January next year.

"We want to make sure that Soviet nuclear reactors, their telecommunications system, their entire production system is working efficiently and effectively," Mr Richardson said.

Japan's nuclear accident has highlighted the need for co-operation

The agreement also calls for a much tougher framework for the registration, monitoring and transportation of nuclear materials in Russia.

The US has long been concerned about the potential for nuclear accidents in Russia and the drain of material and expertise to countries seeking a nuclear arsenal.

However, officials admit that much of its impact will depend on how fully it is implemented by the Russian authorities.

Crisis centre

Mr Adamov said the new crisis centre would help in "accounting for and keeping track of the movement of special materials".

He said the facility was intended to restore effective and reliable lines of management which "were partially lost after the disintegration of the USSR".

It also provides a video hotline between the US and Russia, and other facilities in Europe and Asia.