The Russian Prosecutor-General’s office will look into all circumstances of Monday afternoon’s blast on a St. Petersburg metro train, including security measures, PGO spokesman Aleksandr Kurennoi told the Vesti-24 television news channel, TASS reports.

“We offer our condolences to the families of those killed and all those affected,” Kurennoi said, adding that the investigative authorities were already probing into the explosion, but the prosecutors would examine absolutely all aspects of the affair.

“We will do our utmost to clear up the factors that made the terrorist attack possible to rule out such cases in the future,” he said.

St. Petersburg’s prosecutor Sergey Litvinenko is coordinating law enforcers’ activities on site.

About 10 people have been killed in an explosion between two underground stations in St Petersburg.

The head of Russia’s National Anti-Terrorist Committee said the blast hit the train between Sennaya Ploschad and Tekhnologichesky Institut stations.