Russian President Vladimir Putin has said the human cost of storming a Moscow theatre last month where hostages were held by Chechen rebels was high, but he had no doubts about the need to do it.

He was speaking during a meeting with surviving cast members of the musical Nord-Ost who were among some 800 people seized by a band of Chechen rebels.

It was his first direct response to criticism both in Russia and abroad over the high civilian toll of the rescue operation.

At least 120 hostages died during the crisis - 118 of them through the effects of a gas used to incapacitate the attackers. Two died after being shot by the gunmen.

'Terrible tragedy'

"We had never faced a situation of such complexity before, yet no-one had any doubt for even a second that the operation was necessary," Mr Putin said.

Putin promised the cast government help to restore the musical

"We have come out of this situation at the price of a terrible tragedy, heavy, irreparable losses," Mr Putin said in televised remarks.

Almost 100 of the freed hostages remain in hospitals, six of them in grave condition, media reports say.

"Our nation has lived through a terrible tragedy, a grave ordeal," Mr Putin said.

"The consequences could have been far worse" but for the hostages' "courage, reserve and self-control", he said.

Mr Putin promised the cast that the government would support the restoration of the musical.