By Stephen Dalziel BBC Russian affairs analyst

Mr Putin is facing one of the most severe tests of his presidency

The president said that information had reached him that innocent Chechens in various parts of Russia are under threat.

In the televised extract from his meeting with the Interior Minister, Boris Gryzlov, and the head of the FSB security service, Nikolai Patrushev, Mr Putin stressed that the majority of Chechens living throughout Russia were law-abiding citizens.

He said measures must be taken to prevent any ethnic conflict stemming from the seizure of the theatre by rebels demanding an end to the Chechen conflict.

Pogrom threats

These are difficult times in Russia for Chechens and other peoples from the Caucasus.

The hostage-takers say they are ready to die

Ever since Chechens were blamed for the bombing of two blocks of flats in Moscow in September 1999, those with the swarthy appearance of Caucasian peoples have been subjected to regular security checks in the Russian capital.

There has also been a significant rise in the number of ethnically motivated attacks on Caucasians.

But the hostage-taking in Moscow is clearly making Russian people nervous throughout the country.

The Interior Ministry in a village in the Tver region, to the north-west of Moscow, says it has taken measures to prevent a pogrom - or persecution - against the sizeable local Chechen population.

And the authorities in St Petersburg say that in the last two days they have received a number of letters and e-mails calling for violence against Chechens who live in the city.

The Interior Ministry has set up a telephone hotline for citizens to ring in with any information about threatened racial violence.