So far they are still holding the audience hostage, claiming that they have mined parts of the theater.

Russian media said there were some 700 people in the hall, but the number was not independently confirmed.

Valeri Gribakin, spokesman for Moscow's interior agency, said the number of the hostage takers was 40 to 50 and their only demand was to end the Chechen war. They said so far about 150 women and children have been released.

Police units and an Alpha special forces unit went to the scene and sealed the area. Reinforcement continues to reach the spot. Transportation was cut off in the area, where relatives of the hostages were waiting in cold and wet weather.

President Vladimir Putin, who was immediately informed of the accident, is holding an emergency session in the Kremlin, said Putin's press secretary Alexei Gromov.

Prosecutor General Vladimir Ustinov has arrived on the spot. The police have been told to move everybody to at least 500 meters away from the building.

Olevjina Bobova, an actress of the show, escaped from the third floor of the hall by climbing out of the window through a "rope" made with curtain.

She told Xinhua outside the hall that some 20 attackers, including men and women who speak in Georgian and Chechen accent, entered the concert hall at about 21:00 Moscow time (1800 GMT) and had fired intensively into the air.

She said the gunmen had released Georgians and children, but most of the more than 600 audience and the show staff were still being held hostage.

The attackers had grenades and explosive devices with them, she said.

The wife of a young held actor told Xinhua that the attackers would blew up the whole building if the police launch storms against them.

The Chechen rebel site Kavkaz.org said the attackers were under the control of the Chechen field commander Movsar Barayev.

They staged the assault for demanding the withdrawal of Russian federal troops from Chechnya, the web site said, citing Barayev. He also said the bombs had been planted in the building.

The Moscow police have tightened security around the city's major installations, especially the government building, power stations and oil refinery.

Interfax said one of its reporters was inside the concert hall at the time of the raid. She said by telephone that the gunmen prevented the audience from leaving the theater, but allowed them to make telephone calls.

The Moscow police headquarters reportedly that some children as well as Muslims had been allowed to leave the theater.

The concert hall, located in southeastern Moscow, was staging a performance of the musical Nord-Ost, one of the Russian capital's most popular productions.

(Xinhua News Agency October 24, 2002)