Russia ups security amid alert

Three metro bombs killed 50 people in 2004

Russia increased security in cities around the country on Wednesday after its intelligence chief warned of a terrorist attack on public transport.

Phone operators in Moscow also switched off signals in the metro in an apparent attempt to stop mobiles being used to detonate explosives.

In a highly unusual move correspondents said Moscow broadcast statements on the terrorist threats on Russian TV.

Authorities finally called off the alert citing a lack of evidence.

A spokesman for the national anti-terrorism committee said no evidence had been found to support information - from what he called foreign colleagues - that an attack was imminent.

However, Nikolai Sintsov said the extra security measures introduced across Russia had reduced the risk of an attack.

Tight security

Late on Tuesday, the head of the Federal Security Service (FSB) announced foreign intelligence had indicated an attack was being planned.

Nikolai Patrushev gave no further details on the origin or nature of the information.

But officials moved to assure the public that all was being done to tighten security around key civilian, government and military facilities.

Extra police were deployed in all of the country's major cities, with an increased presence on the underground and train stations as well as airports.

The last major attack on Moscow's metro system was three years ago, when two bombs killed more than 50 people.

The authorities blamed that attack on Chechen rebels. Russia has for 12 years fought a bloody campaign to suppress an insurgency in the region.