The Chechen warlord Shamil Basayev, who ordered the Beslan school siege, has warned he is planning further attacks.
The rebel leader made the threat in an interview with Britain’s Channel 4 News, filmed about three weeks ago.
Moscow condemned Thursday’s broadcast as “irresponsible”. It also rejected an apparent Chechen ceasefire offer, made on Wednesday, as a bluff.
More than 320 people – half of them children – were killed in the siege at a school in Beslan in September.
Rebels had stormed the school in the Russian province of North Ossetia, taking more than 1,000 children, teachers and parents hostage.
As the rebels set off bombs and the siege descended into a battle between them and Russian security forces, scores of civilians were killed.
Mr Basayev is also blamed for other attacks in which dozens have died, and is regarded as Russia’s most wanted man.
He told Channel 4 News he blamed the Russian security forces for the massacre at Beslan.
“To be honest, I am even shocked by what happened there and am still in a state of shock after it,” he said.
“We are planning Beslan-style attacks in the future. Cynical though it may look, we are planning these operations, and we will conduct them, if only to show the world again and again, the true face of the Russian regime.”
He said Russian civilians were accomplices in Moscow’s war with Chechen separatists, because they paid taxes and did not speak out against it.
“It’s just that they don’t all have weapons in their hands.”
During the video, Mr Basayev wears a T-shirt bearing the legend “anti-terror”, and quotes Winston Churchill alongside the Koran.
The Russian foreign ministry said broadcasting the interview amounted to “informational support of terrorists”.
It said it had called on British authorities to stop the broadcast.
The British Foreign Office said while it “absolutely and unreservedly condemns Shamil Basayev’s involvement in terrorist activities”, it was not its responsibility to prevent the transmission.
Channel 4 said it believed Mr Basayev’s rationale should be “subjected to scrutiny”.
On Wednesday, it was reported on a pro-Chechen rebel website that Mr Basayev and Aslan Maskhadov, the former elected president of Chechnya, had called a ceasefire for the month of February as “a display of good will”.
However, the BBC’s Sarah Rainsford in Moscow says the ceasefire is said to expire on 22 February – the day before the anniversary of Stalin’s deportation of the Chechens to Central Asia – fuelling speculation the rebels could be planning an attack if their ceasefire gesture is ignored.
Meanwhile, the Russian news agency Interfax reported that rumours were circling that Mr Basayev had been killed in a clash with foreign mercenaries.
There have been frequent claims of the warlord’s death in the past, only for him to surface claiming responsibility for the latest bloody attack.