Amidst a rising tide of anti-Chechen feeling, Russian President Vladimir Putin insisted that it was too early to blame Chechen rebels for Tuesday's bomb atrocity in the center of Moscow which killed eight and maimed dozens.

Leaders of the large Chechen community in the city and Russian Muslims voiced alarm at the incendiary statements from some senior political figures which encouraged reprisals against Chechens, while racist demonstrators paraded at the site of the tragedy declaring that the "only good Chechen is a dead Chechen."

In a statement on television, Putin said that "a crime was perpetrated, either the result of a criminal feud or an act of terrorism. Discussing the terrorist version, I have to state that it is not right to seek a national trace, a Chechen trace, or any other in this crime. ... It's not correct to brand an entire nation."

The statement was seen as an attempt to cool Muscovite tempers and a rebuke to the powerful Moscow Mayor Yury Luzhkov, who was quick to denounce the bomb as "100 percent Chechen" while his aides declared that Russia was in a state of war (with the Chechens) and that freedom of movement would need to be restricted.

It was also clear that Putin's government believed that Chechen terrorists were responsible. One Chechen man and another from neighbouring Dagestan were detained for questioning though they were not suspects in the blast.

Three suspects were being sought, two of them officially described as being of "North Caucasian appearance."

Another three Chechens were arrested in the town of Saratov with bomb equipment said to be in their possession. They "might have been planning a terrorist attack similar to that in Moscow," Interfax reported.

And Nikolai Patrushev, the head of the domestic security service and close Putin associate, said 11 other bomb plots in various Russian cities were foiled last month.

While some 1,600 police launched a security sweep across Moscow, checking papers, searching vehicles, patrolling railway and subway stations, and inspecting flats, the city's Chechen leaders said they feared the kind of harassment and repression that followed last year's bomb blasts, which killed 300 in Moscow and other Russian cities.

"We can see the problems coming for Chechens all over Russia. We're extremely worried and the official statements are encouraging this," said Dzhabrail Dzhokalayev, the head of an organization representing the Chechen diaspora in Russia.

"What happened in Moscow yesterday is happening in Chechnya every day. We're suffering more from terrorism than anyone else. It's very dangerous for Russia to defame an entire people in advance." He said Putin's statement had been reassuring.

The religious leader of Russia's Muslims, Sheikh Ravil Gainutdin, said: "Politicians and public figures should be very cautious so as not to spark nationalist feuds."

The scene of the blast at Pushkin Square, a few hundred yards from the Kremlin, was thronged with people engaged in heated debate about the atrocity and who was responsible.

"This would never have happened if our security services were working better," said Tamara Ivanovna, a crockery seller working in the underpass at the time of the explosion Tuesday evening. "They knew something like this was going to happen and they didn't stop it. This was a terrorist attack."

Passersby laid flowers and bottles of vodka and beer at two makeshift shrines to the victims in the charred ruins of the pedestrian underpass.

There was no lighting, and burnt wires and piping hung from the ceiling, but thousands of Muscovites passed through, going about their normal business. Several women wept on seeing the carnage, and one young man fainted in the crush of people.

Putin launched the war in Chechnya last year in response to a series of bomb attacks blamed on Chechen secessionist rebels, although the allegations have never been proven. But the measured nature of yesterday's statement suggested the president was fearful of lighting a touchpaper which could spark a bigger conflagration.

The risks of such conflict were illustrated a fortnight ago when a Russian mob went on the rampage in a Volga village in southern Russia, stoning Chechen homes and torching several flats after a disco brawl in which two Chechens killed a Russian youth.