Russia's security body on Friday formally ended a high alert announced earlier this week over a threat of terror attack.

Nikolai Patrushev, the Federal Security Service chief who also chairs the National Anti-Terror Committee, ordered the alert to be ended as of early Friday, a duty officer at the agency said on condition of anonymity because he was not authorized to speak to the media.

The alert involved thousands of extra police deployed at Moscow subway and other public transport facilities around the nation.

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The committee issued the alert warning after receiving information about a possible terror attack on public transport from unidentified foreign nations.

As part of the increased security, uniformed police, some with bomb-sniffing dogs, patrolled subway and train stations as well as other sites around Moscow, checking documents and standing guard at entrances. Public announcements asked passengers to be on alert for suspicious items.

Moscow's three main international airports introduced stricter passenger checks and additional police patrols of terminal buildings.

The National Anti-Terror committee said Friday that the alert had boosted public vigilance, adding that it would continue the practice of issuing public warnings.

Russia has seen a spate of high-profile terrorist incidents in recent years, including hostage takings and subway and airline bombings linked to the 12-year conflict in mostly Muslim Chechnya, where large-scale fighting ended years ago but an insurgency continues.

In February 2004, an explosion ripped through a Moscow subway car during rush hour, killing 41 people. In August 2004, a suicide-bombing just outside a Moscow subway station killed 10 people.

Also in August 2004, suicide bombers who boarded their planes at a Moscow airport blew up two Russian passenger jets that exploded almost simultaneously, killing all 90 people on board.

The Kremlin has scored a series of notable successes in its fight against terrorism, including the death in July of Chechen warlord Shamil Basayev, who claimed responsibility for some of the nation's bloodiest terrorist attacks.

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