Russian investigators detain six on terror suspicion, no links to bomb attack

No one has so far claimed responsibility for the attack.

They have also detained several people suspected of being accomplices of the man behind the metro bombing, Russian news agencies have reported.

The bomb detonated inside the train as it travelled between two major hub stations in the centre of the city.

ST. PETERSBURG, Russia (AP) - As the residents of Russia's second-largest city try to regain their nerve in the wake of a fatal subway bombing, officials announced Wednesday that six people have been arrested on suspicion of recruiting others to commit extremist crimes.

"Objects relevant to the investigation were found during the search of the apartment where these people lived", the Investigative Committee said.

Russian security agencies have been checking Dzhalilov's contacts in St. Petersburg, while Kyrgyz law enforcement agencies have been talking to his parents in the impoverished nation.

"Shocked & saddened by news of terror blast in St Petersburg; my deepest condolences to bereaved families, people & government of Russian Federation", he tweeted Tuesday.

The prime minister expressed his condolences over the dead and his sympathy with those injured in an explosion in the subway system in St. Petersburg on Monday that killed 14 people.

Fragments of his body were found on one of the train carriages and his DNA was also discovered on a second bomb defused shortly after the blast.

People carry a subway blast victim into an ambulance after a Monday explosion at Tekhnologichesky Institut subway station in St.Petersburg, Russia.

Train doors were blown apart by the underground blast in St Petersburg on Monday.

In an apparently unrelated incident, two traffic policemen were killed overnight in the southern city of Astrakhan when unidentified assailants opened fire on them, the regional governor said, calling them "radical Islamists". The hardline group has been linked to recent attacks elsewhere in Europe.

The attack has put renewed focus on the large number of migrants from central Asian former Soviet states, who have moved to Russian Federation to work. Adding to the curiosity is a terrorist attack at almost the same time that killed two police officers in Astrakhan, a Caspian Sea city near Kazakhstan, and just a few hours' drive from Chechnya.