The female suicide bombers who killed dozens of people in the Moscow metro on Monday were likely avenging the death of their trainer and inspirational leader, a Muslim convert who was slain by FSB commandos earlier this month.
Since the first female suicide bomber blew herself up in 2001, so-called "black widows" have participated in two-thirds of the nearly 40 rebel attacks that have killed about 900 people in Russia through Monday.
Other radical groups around the world — in the Palestinian territories, Turkey and Sri Lanka — have also deployed women as walking bombs, but the percentage of their involvement in overall suicide attacks is in the single digits.
After a series of horrific attacks fr om 2001 to 2004, a four-year lull was broken in late 2008 with a spate of bombings linked to Said Buryatsky, a Muslim convert born as Alexander Tikhomirov who quickly rose within the rebels' ranks as their chief ideologist.
Several rebels detained en route to suicide attacks told law enforcement officials that they had been trained by Buryatsky. In his own diaries posted on the rebel web sites Hunafa and Kavkaz Center, Buryatsky told of how he had convinced suicide bombers to take part in bombings last year.
Federal Security Service commandos killed Buryatsky in a special operation in Ingushetia on March 2.
The FSB said at the time that 30 suicide bombers trained by him remained at large.
Two of them were behind Monday's bloodshed, said Alexander Torshin, first deputy speaker of the Federation Council and head of the chamber's commission on the North Caucasus.
"It seems to me that the terrorist attacks in the Moscow metro were a response to attempts to eliminate odious North Caucasus fighters like Said Buryatsky," Torshin told Interfax. "They, these militants, live in a cold, vengeful environment."
He said the decision to target the Lubyanka metro station — located below FSB headquarters — spoke volumes about the attackers' motives. "Lubyanka was not chosen accidentally because FSB employees were traveling to work at the time," he said.
"Black widows," as Russian journalists have dubbed female suicide bombers, are the proven weapon of choice for Islamist rebels from the North Caucasus.
The first "black widow," a young Chechen named Luiza Gazuyeva, killed a Russian general in Chechnya in November 2001 because she believed that he was responsible for the death of her husband. North Caucasus rebels did not claim responsibility for the attack but quickly moved to capitalize on the public shock of women willing to kill and die for their cause. Before the end of the year, rebel warlord Shamil Basayev announced that he was creating a battalion of shahids, or religious martyrs, called Riyadus Salihin, or Gardens of the Pious, that would be staffed by both men and women.
Russia's envoy to NATO, Dmitry Rogozin, urged journalists on Monday not to call the metro bombers "shahids" because this might provoke sectarian violence.
"They are in no sense shahids," he said, Itar-Tass reported. "We should not allow the suicidal terrorists who killed dozens of innocent people to be called religious martyrs. They are murderers."
Female suicide bombers have participated in almost every attack claimed by Riyadus Salihin, starting with the 2002 Nord-Ost hostage-taking in Moscow and three attacks the following year: the bombing of a Moscow rock concert, the bombing of a commuter train in Yessentuki and the self-detonation of a woman outside Moscow's National Hotel.
Female suicide bombers were blamed for bringing down two passenger planes en route from Moscow and a bombing outside the Rizhskaya metro station in August 2004. They also participated in the Beslan school hostage-taking in September 2004.
During the four-year lull that followed, Basayev was killed by federal forces in July 2006.
Then a female bomber blew herself up at a bus stop in Vladikavkaz in November 2008. Last year, suicide bombings again became the tactic of choice for rebels, with six attacks being carried out in July alone in the North Caucasus. Some of the attacks were reportedly carried out by women.
Several attempts have been made to profile female suicide bombers originating in the Northern Caucasus. The broadest study was conducted by journalist Yulia Yuzik, who wrote in her 2003 book, "The Brides of Allah," that they do not have a single, clear profile. Her book, based on interviews with the families of female suicide bombers, found that the bombers are of all ages and do not necessarily share a history of violence perpetrated against their families. Many are indeed widows whose husbands were killed in federal anti-terrorism operations. But not all of them were religious before they left their homes to join the rebels.
Terrorism experts have debated what attracts the women to participate in the attacks. Some say the low social status of widows and single women in Chechnya make them easy to recruit, while others say women are more emotional than men and therefore easier to convince to stage suicide attacks.
But unlike in the Palestinian territories and Sri Lanka, wh ere terrorists began deploying women as living bombs after security services made it all but impossible for male attackers to get to their targets, the North Caucasus rebels have used women from the start of their suicide strategy in 2001, which suggests that they placed their bets on women from the very beginning.
Since then, the rebels have managed to cultivate a high level of fear with female suicide bombers, making it strategically unwise for them to any longer send men on suicide missions to Moscow.