Bomber in Russian attacks is 17-year old Chechen widow

One of the suspects in last week's Moscow bombings is a 17-year-old widow of an Islamist militant from the North Caucasus. She is suspected of blowing herself up in suicide attacks that killed 40 people in Moscow.

More than 50 people were killed and another 100 injured in suicide bombings this week in the Moscow metro and in a town in the turbulent North Caucasus region of Dagestan, raising fears of a new bombing campaign against the Russian heartland.

She has been named as Dagestani-born Dzhennet Abdurakhmanova, the widow of 30-year-old Umalat Magomedov, a prominent insurgent killed by Russian forces on December 31.

Abdurakhmanova also used the name of Dzhanet Abdullayeva, the source said.

Magomedov, who was shown in the photographs holding a pistol, styled himself as the "Emir of the mujahideen of the Vilayat Dagestan," a local Islamist group, the source said.

Officials said two female suicide bombers -- known in the Russian media as "Black Widows" -- killed at least 40 people on packed Moscow metro trains during the rush hour on Monday.

"Black Widows" is a term for the widows of Islamic militants killed by Russian forces.

The first bomb tore through a metro train just before 8 a.m. as it stood at the Lubyanka station, close to the headquarters of the FSB. A second bomb was detonated less than 40 minutes later in a train waiting at the Park Kultury metro station.

The suicide bombings in Moscow and Dagestan follow a surge of violence over the past year in the patchwork of North Caucasus republics, where Russia has fought two wars against Chechen separatists since the 1991 fall of the Soviet Union.

Islamist Chechen rebels claimed responsibility on Wednesday for the Moscow metro bombings and threatened further attacks against Russian cities.

Chechen rebel leader Doku Umarov, who calls himself the "Emir of the Caucasus Emirate," said he had ordered the twin suicide bombings in Moscow to "destroy infidels" and in revenge for Prime Minister Vladimir Putin's policies in the North Caucasus.