ST. PETERSBURG, April 3. /TASS/. Russian President Vladimir Putin expects that investigators will soon get to the bottom of what caused Monday’s blast in St. Petersburg’s metro.

The president said that now the investigators are looking into various theories, including those linked to terrorism. "The causes (of blast) are unclear, that’s why it is still early to speak about this now. The investigation will determine what happened," Putin said at the meeting with Belarusian President Alexander Lukashenko.

"Certainly, all causes are being considered, both common crime and manifestations of terrorism. We will see. The investigation will soon provide all answers to what has happened," the president assured.

The Russian leader offered condolences to the relatives of those killed or injured. Lukashenko also offered condolences to Putin and to the people hurt in the blast.

Putin said he had received reports from special services on the blast in the St. Petersburg metro. "I have already talked to the heads of special services and the director of the Federal Security Service," he said. "The law enforcement agencies and special services are working and will do everything to establish the causes of the incident and to provide a full assessment on what has happened," Putin explained.

A blast ripped through a subway car between the Sennaya Ploshchad and Tekhnologichesky Institut stations at around 2.40 p.m. Moscow time (11.40 GMT).

According to preliminary reports, ten people were killed by an explosion, emergency services told TASS. An unidentified device exploded in the train car, a source said. About 50 people were hurt in a blast in the St. Petersburg metro system, spokesman for the city’s governor Andrei Kibitov said.