Eighteen persons were killed and 60 injured in Russia when two suicide bombers blew themselves up at an outdoors rock festival in capital Moscow.

It is feared that the toll could rise as the police are yet to examine the fragments of bodies strewn in the area, which has been cordoned off by the military and federal security service (FSB) personnel.

The stringent security measures at the Kriliya (the Wings), an annual rock festival at the Tushino airfield in north Moscow, prevented the two female suicide bombers from entering the crowded venue where over 40,000 spectators had converged.

One of suicide bombers blew herself near the queue at the booking office and another at the gate of a nearby bustling market.

In order to prevent panic and a stampede among the spectators after the blasts, authorities had immediately switched off the networks of all the cell phone operators in the area and evacuated people in special buses.

"The rock festival is going on and the spectators are unaware of the blasts," one of the organisers had told Rossia, a television channel.

Police recovered an identity card from the body of one of the suicide bombers, which said she was Zulikhan Likhajiyeva (20), a resident of Chechan village of Kurchaloi.

FSB Director Gen Nikolai Patrushev cut short his tour of the Volga region and rushed to Moscow.

US President George W Bush expressed solidarity with Russia following the terror attacks.

"Today, freedom is under threat. We have become witnesses of a horrifying terror attack," RIA Novosti, quoting US Ambassador Alexander Vershbow who read out President Bush's message at a function in Moscow to mark the American Independence day, stated.

Bush also sent condolence message to the kin of the victims.

Condolences poured in from leaders of various countries, including France, Germany and the CIS nations.

In June, a female suicide bomber killed at least 17 people after throwing herself at a bus carrying Russian military personnel, on the outskirts of Mozdok in southern Russia.

Last year, Chechen rebels targetted a Moscow theatre, holding more than 100 people hostage. Russian special troops stormed the building after letting off a mystery gas.