Via Interfax:

U.S. President George W. Bush telephoned his Russian counterpart, Vladimir Putin, expressing his condolences over deaths caused by recent terrorist attacks in Russia and offering his sympathy over Wednesday's hostage crisis in North Ossetia.
Bush also offered any form of support Russia might need to release the hostages, the Kremlin press service told Interfax.
The U.S. president said his country and Russia were fighting international terrorism shoulder to shoulder.

Also, Kofi Annan speaks out:

U.N. Secretary-General Kofi Annan urged the terrorists to release the children, their parents and teachers who were taken hostage in a school in North Ossetia on Wednesday. In his statement that has just been circulated in the U.N. Annan said he was “shocked” by the incident and condemned it in the strongest possible terms.

And a little background on North Ossetia, via Wikipedia:

Historically, right River Terek bank of Prigorodny District had been part of Ingushetia, but was granted to North Ossetia in 1944, following Stalin's deportation of the Ingush to Central Asia. Although they were eventually allowed to return to their homes, the territory itself was never returned to Ingushetia, causing considerable tension in the region. A local law, passed in 1982, actually prohibited ethnic Ingush from obtaining residency permits in the republic. The massive influx of South Ossetian refugees in the early 1990s and the ensuing conflict between the two rival groups eventually caused many Ingush to flee to Ingushetia. While efforts are underway to settle the refugee problem, the conflict between the two republics has yet to be resolved.

UPDATE:

An official statement from Umar Khanbiyev, described as General Representative of the President of the Chechen Republic of Ichkeria to foreign countries, but also described to me as a health minister.

We have become eyewitnesses to a number of inhuman atrocities by people — of explosions in Moscow and the hostage-taking of schoolchildren in the town of Beslan, widely reported by Russian and world media.

There is no justification for this inhuman action, as there is no justification either for the murder of 42 thousand Chechen school-age children by the Russian military, carried out on the order of the Kremlin regime and Putin personally.

The genocidal war against the people of the Chechen Republic of Ichkeria and the criminal-terrorist policy of the Kremlin regime are the detonator for destabilization in the entire Caucasus and in Russia itself. The countless crimes against humanity, committed by Russia on Caucasian soil, are making possible desperate, inhuman reciprocal steps, like today’s action by people who have lost their senses because of grief and losses, because of cynicism and injustice.

Confirming the unacceptability of any terrorist methods against peaceful civilians for the achievement of political goals, I am authorized to state on behalf of the President of the Chechen Republic of Ichkeria, Aslan Maskhadov, as well as the Government of the Chechen Republic of Ichkeria, that the further escalation of the policy of terror against the peoples of the Caucasus, including the people of the Chechen Republic of Ichkeria, is fraught with the loss of control of the situation, with unpredictable consequences, and that the moral and juridical responsibility for this is lying personally with the President of the RF, Putin, and his clique.

Via Lenat.ru and loosely translated with Babelfish, it seems that Shamil Basayev is denying any involvement with the hostage taking.

Anyone read Russian?