Russia has identified a 17-year-old widow of a Caucasus militant as one of the Moscow suicide bombers, reports said on Friday, as the country remained on high alert after the attacks.
Citing sources close to the investigation, the Kommersant daily named one of the two female suicide bombers who blew themselves up on the Moscow metro Monday as Dzhennet Abdurakhmanova, 17, from Dagestan in the North Caucasus.
The newspaper published a photograph of the baby-faced teenager in an Islamic headscarf with her late husband Umalat Magomedov. Both were posing casually with pistols.
The reports came as Russia remained tense after the Moscow bombings and the another double suicide strike Wednesday that killed 12 in a town in Dagestan close to Chechnya.
With the authorities rattled by the deadliest militant bombing in the capital for six years, President Dmitry Medvedev on Thursday had urged tough anti-terror measures as he made a surprise visit to Dagestan.
Kommersant said Abdurakhmanova's husband Magomedov was a Dagestani Islamist rebel killed in a special operation last year, the newspaper reported citing investigators in Dagestan.
Her name Dzhennet, found among Muslim women in Russia, is derived from the Arabic word Jannat, meaning paradise.
Russian investigators believe that Abdurakhmanova was responsible for the first of the double suicide blasts on Monday which together killed 39 people.
The bombings sent a chill across Russia, recalling the string of suicide attacks carried out earlier in the decade by the so-called "Black Widows", women found to have been relatives of men killed by Russian forces.
Investigators have not officially identified the second bomber, but one version is that she was a Chechen woman called Markha Ustarkhanova who was also married to a Caucasus militant, Kommersant reported.
Ustarkhanova, 20, is the widow of a rebel from the Chechen town of Gudermes, Said-Emin Khizriyev, who was killed in October last year, Kommersant reported.
However, a source in the Chechen security forces told the RIA Novosti news agency Thursday that investigators had examined a photograph of Ustarkhanova, who is listed as a missing person in Chechnya, and found it did not match shots of the corpses of the Moscow bombers.
The Russian authorities have released grisly photographs showing the severed heads of the two women's corpses, which are the prime evidence in the police investigation.
The two women who staged the bombings are believed to have taken a bus from the Dagestan town of Kizlyar, where the double suicide bombing killed 12 on Wednesday, and arrived in Moscow early Monday, reports have said.
On Friday, security forces announced that police had defused a third "powerful" bomb in a cemetery in Kizlyar Wednesday, Russian news agencies reported.
The Islamist group "Emirate of the Caucasus", which is waging an insurgency to impose an Islamic state based on sharia law in the North Caucasus, claimed the Moscow attacks in a video message from its shadowy leader.
Doku Umarov, who has been the target of several attempts to kill him by the Russian security forces, said in a video posted Wednesday that he personally gave the order for the strikes on the metro.
"It is a legitimate act of revenge for the continued assassinations of civilians in the Caucasus," he said in the video posted on the kavkazcenter.com website which is frequently used by militants to post messages.
Russia has for years battled Islamist insurgents in the North Caucasus Muslim regions of Dagestan, Chechnya and Ingushetia. But Monday's attacks were the first time in six years that such violence has spread to the capital.