By Stephen Mulvey BBC News Online

If confirmed, it will be the latest in a long line of suicide bomb attacks in Russia - most of them blamed on Chechen rebels.

It is more than 18 months since President Vladimir Putin said the war in Chechnya was over - but Russia is increasingly coming to realise that a new kind of war may be under way.

Thousands of Russian forces remain in Chechnya

Experts are talking about the "Palestinisation" of the conflict - and pointing out that Israel has been powerless to halt suicide bombers.

The first suicide bombings took place in Chechnya in June and July of 2000, but in the last year they have become regular occurrences.

The list includes:

• A lorry-bomb attack on the Grozny administration at the end of December 2002, which left 80 people dead.

• A carbon copy of that attack in Znamenskoye, in the north of Chechnya in May, which left more than 50 dead.

• An attack at a religious ceremony in Chechnya later that month, in which two female suicide bombers apparently tried to assassinate Chechnya's pro-Moscow leader (now Chechen president) Akhmad Kadyrov.

• Another lorry bomb in June, which destroyed a branch of the Federal Security Service in Grozny and a local government building.

• A suicide bomb attack on a bus carrying air force personnel near Mozdok in North Ossetia, the same month.

• An attack by two female suicide bombers at a rock concert in Moscow in July, which killed 15 people.

• Another lorry bomb at a military hospital in Mozdok on 1 August, which killed at least 50 people.

• A bomb attack on a train in the Stavropol region of southern Russia, in December, which killed at least 44 people.

Some 300 people died in these attacks, many thought to have been carried out by Chechen women - the wives, mothers and sisters of Chechen men killed by Russian security forces.

Statistics

The radical Chechen warlord Shamil Basayev, who apparently masterminded the mass hostage-taking at a Moscow theatre in October 2002, has boasted of having a whole unit of female suicide fighters.

The earth will burn under their feet. These animals will never feel safe anywhere Boris Gryzlov, Interior Minister

It is little consolation to ordinary Russians that the Chechen rebel government repeated after the Stavropol rail attack that it respected "international humanitarian law" and condemned acts of violence against civilians.

Nor that Interior Minister Boris Gryzlov issued a blood-curdling threat to the rebels: "The earth will burn under their feet. These animals will never feel safe anywhere."

Statistics show how badly the war has affected both the lives of both Chechens and Russians:

• Thousands of Russian troops remain in Chechnya - some 38,000 were entitled to vote in a March referendum on a constitution for the republic - only a tiny fraction have been withdrawn.
• There are few places where they can feel totally safe. A missile attack on a helicopter in August 2002 killed 116 - the heaviest Russian casualty toll in a single incident since the start of the second Chechen war in 1999.
• The official figure for the number of Russian soldiers who died in Chechnya between 1999 and mid-2003 is 4,705 - though the Soldiers' Mothers of Russia organisation put the figure at 11,000.
• Their estimate for the first Chechen war, which lasted from 1994 -1996 is 14,000 dead, compared with the official 5,500. Civilian deaths in this war are numbered in the tens of thousands.
• More than 250 people went missing in Chechnya in the first half of 2003, according to a member of the pro-Moscow government
• Another government official was quoted as saying that 1,178 people had been killed in the first nine months of 2002, and that 654 people had disappeared.

The disappearances are in some cases linked to a disturbing new trend.