Two blasts in Moscow's metro network on March 29 killed approximately 35 people (reports vary; the number of dead could be as high as 46) and injured more than 100 others. The explosions, reportedly carried out by two female suicide bombers, were timed to hit the heart of the city's public transportation network at its peak morning rush hour. The first explosion occurred at 7:56 a.m. at Lubyanka station as the train pulled up to the platform and passengers entered and exited the train. The blast, which originated from the second car, killed approximately 23 people in the car and on the platform. Forty-three minutes later at Park Kultury, a second, very similar attack occurred. As the train pulled up to the platform and opened its doors, an explosion occurred on a rear train car, killing approximately 12 people. Both train stations are near prominent Moscow landmarks, such as the Federal Security Services offices, the Kremlin and Gorky Park. Several items outlined in the special guidance STRATFOR issued immediately after the attack
have materialized, providing more clues as to who was responsible for the attacks. No one has claimed responsibility for the attacks yet, but the tactical details emerging point to the involvement of militants from the northern Caucasus. First, Russian investigators have said evidence from the scene suggests the two suicide bombers were female (authorities claim to have discovered their heads). The use of female suicide operatives is significant, as Chechen militants commonly use women — who generally attract less suspicion than men — as suicide bombers. Female Chechen suicide bombers referred to as "black widows"
were used in many plots against civilian targets in Russia, including subways and rock concerts, and in attacks on board two crashed airliners in 2004
. Female suicide bombers' involvement in the March 29 explosions supports the idea that militants from the northern Caucasus carried out the attacks. Furthermore, Russian media have reported that the devices contained nuts and bolts, which acted as deadly projectiles in the blasts. Packing shrapnel around explosives to maximize the casualty count in a bombing is a tactic used by many militants around the world, including Chechen operatives. Also, authorities have confirmed that the explosive material used in the attacks was TNT, which is frequently used by a number of militant groups, including those from the northern Caucasus. Suspected militants from the northern Caucasus have used TNT in several high-profile attacks, most recently in the November 2009 Nevsky express train bombing
(involving a device containing approximately 30 pounds of TNT but using very different tactics) that killed 39 people and the attempted assassination of Ingush President Yunus-Bek Yevkurov
in June 2009 that involved an improvised explosive device containing 130 pounds of TNT. Although use of shrapnel and TNT is hardly unique to militants from the northern Caucasus, the devices used in the March 29 attacks had the same components used in devices in previous attacks carried out by northern Caucasus militant groups. Reports on the sizes of the devices vary; the device used in the Lubyanka station attack is said to have been between 3 and 8 pounds, and the device in the Park Kultury attack is said to have been between 1 and 4 pounds. Both operatives reportedly wore explosive belts that would be easily concealed by winter coats. Although larger devices can be engineered, it would make sense for these operatives to use smaller devices to reduce the risk of detection. The reported sizes of the explosive devices match up with the reports of the number of deaths in both attacks. In a very similar attack in February 2004 against a train on the metro's green line, a single suicide bomber killed 41 people by detonating a device that reportedly contained 8 pounds of TNT. That attack was later claimed by a Chechen militant group. Russian security officials reviewing surveillance footage of the attackers said the operatives boarded their respective trains at the Yugo-Zapadnaya station (the last stop on the red line in southwestern Moscow; security is more lax in the suburbs than in central Moscow). They appeared to be accompanied by two other women and a man; however, it is unclear how these individuals might have been connected with the bombers. They could have been handlers ensuring that the operatives got to their destinations securely, or they could have been uninvolved individuals who simply boarded the trains at the same time. Details about these possible accomplices should be watched to determine the nature of their involvement. In addition to all of these tactical details, the timing of the attack also matches with past attacks carried out by northern Caucasus militant groups, who take advantage of the spring thaw to increase attacks against Russian targets. Most of these attacks take place in the northern Caucasus regions of Chechnya, Ingushetia and Dagestan, but as demonstrated in attacks over the past decade militants from these regions are capable of reaching Moscow and other regions in the Russian core. For this reason, security in Moscow (especially within the metro system, which is an established target) is usually stringent. However, public transportation systems
around the world — not just Moscow's — are notoriously difficult to secure, meaning that no matter how tight security is, successful attacks are inevitable.