There is still no end to a hostage crisis in Russia, where heavily armed Chechen separatists are holding hundreds of people at a theater in Moscow.

The hostage-takers have threatened to blow up the theater or kill many of those inside if Russian security forces attempt to storm the building.

Many hostages have been able to call out on their mobile phones to their families or members of the media. They say they have little to eat and are exhausted from the long ordeal. There has been little official information about the hostage situation.

It began Wednesday evening when about 40 heavily armed men and women broke into a theater in southeastern Moscow where spectators were watching a musical.

During the night, separatists are said to have released children and non-Russians, including Muslims. A number of audience members or actors who were starring in the musical managed to escape, some by climbing out a window.

Witnesses say the heavily armed Chechens broke into the building during the second act of the play, fired automatic weapons and demanded an end to the war in Russia's breakaway region of Chechnya.

Separatists have been fighting Russian troops for the past three years in Chechnya.

A Chechen lawmaker has been trying to negotiate with the hostage-takers but so far to no avail.

A number of foreigners are reported to be among the hostages. Representatives from many of the embassies in Moscow, including Austria, Germany, Britain and the United States, were on the street near the theater Thursday and there were reports that the foreigners would be released, although this could not be confirmed.

The hostage crisis has riveted the country. Russian President Vladimir Putin, in his first official reaction since the crisis began, told Russian news agencies forces must free the hostages with maximum safety.

Mr. Putin canceled a trip to Germany and Portugal that he was scheduled to take Thursday.

Police have been trying to close off the area around the theater and have been evacuating people from nearby buildings.

Russian troops have been fighting separatists in Chechnya for three years. In 1999, a series of apartment bombings rocked Russia and killed about 300 people. Russian officials blamed the bombings on Chechen separatists and cited the bombings as a reason to invade Chechnya.

This is the second military campaign Russia has waged in Chechnya since the fall of the Soviet Union. Russian forces invaded Chechnya in 1994 only to withdraw in 1996 in a harsh defeat.