The suspect in the suicide bombing of the Volgograd train station — the first of back-to-back attacks in the Russian city — has been identified as a recent convert to Islam who rebuffed his parents' plea to leave the insurgency and come home.
Police say Pavel Pechyonkin, a former paramedic, carried out the blast that killed 18 people and renewed concerns about security for the Winter Olympics in Sochi six weeks from now.
A second bombing less than 24 hours later blew a trolley bus to bits and killed 13 people. No suspect has been identified in that attack.
Pechyonkin, 26, reportedly converted to radical Islam in 2011 and when he went underground, his parents feared he had joined an armed group in Dagestan, Russian and foreign media reported.
They posted a video online appealing for him to return.
"Come home," his mother said in the video. "We see how many people die because of people like you."
His father added, "Don't harm people...not matter what their religion."
Pechyonkin was unswayed and posted a video response.
"It is not easy to go this way, the way of jihad," he said. "But Allah makes us strong.'
No group has yet claimed responsibility for the bombings, which have sent thousands of Russian police officers through Volgograd's coffee shops and markets on a hunt for accomplices.
Dozens of people have been detained, though it's unclear if any were connected with the carnage.
"We will confidently, fiercely and consistently continue the fight against terrorists until their complete annihiliation," Russian President Vladimir Putin said.
The violence in Volgogrod comes amid a threat by Chechen warlord Doku Umarov, who has claimed responsibility for similar attacks in the past, to disrupt the Sochi Games.
“We’re concerned,’’ Scott Blackmun, CEO of the U.S. Olympic Committee, told Matt Lauer Tuesday on TODAY. “I think this is the first time that we’ve had an incident so close to the Games both in terms of geography and in terms of time.
"The reality is that there are different challenges at every Games. In this case we got a preview of what could happen, but we’re very hopeful that the Russians’ commitment to security, which is frankly one of the highest levels of commitment we’ve ever seen from a government and an organizing committee, will serve us well."