Two female suicide bombers killed 37 passengers in the Moscow subway system today, blowing themselves up in crowded train cars. Chechnyan terrorists are suspected in the attack:

The head of Russia’s main security agency said preliminary investigation places the blame on rebels from the restive Caucasus region that includes Chechnya, where separatists have fought Russian forces since the mid-1990s. Alexander Bortnikov, head of the FSB, told President Dmitry Medvedev the bombs were filled with bolts and iron rods.

Prime Minister Vladimir Putin, who built much of his political capital by directing a fierce war with Chechen separatists a decade ago, vowed that “terrorists will be destroyed.”

Though the Chechen War has been thought to be over, with most of the Russian troops withdrawn last year, this attack may provoke more violence in the region. Russian counter-terrorism forces may return to the Caucasus.

The White House condemned the attack in a statement.

David Dayen

David Dayen