ST. PETERSBURG, April 4. /TASS/. Four injured in a subway blast in St. Petersburg are in critical condition, almost all of them have barotrauma, Russia’s Health Minister Veronika Skvortsova said Tuesday.

"We are currently in Dzhanelidze Research Institute of Emergency Medicine, 18 patients are here, including four in a severe condition and in critical condition. The issue is about mine explosion trauma, almost all (patients) have barotrauma," she said.

According to Skvortsova, there are patients with internal injuries, traumatic brain injuries, amputated and fractured limbs, as well as burns in the hospital.

As of now, 45 injured in a subway blast in St. Petersburg are at hospital, Skvortsova said. "As of today there are 45 patients at hospital, as of now 11 are killed," the Minister said when she arrived at Dzhanelidze Research Institute of Emergency Medicine where some people injured in the metro blast had been taken to.

The patients severely injured in a subway blast in St. Petersburg have been operated on in Dzhanelidze Research Institute of Emergency Medicine, Veronika Skvortsova said, adding that one more concilium of doctors would be held in the morning.

"All that is necessary is being done. Severely injured patients have been operated on (in Dzhanelidze Research Institute of Emergency Medicine - TASS), we hope for improvement, in the morning another concilium will be held," she said.

According to Skvortsova, two women that are in Dzhanelidze Institute are unidentified.

Ambulance services operated perfectly following the subway blast in St. Petersburg, Russia’s Health Minister said, adding that the first ambulance crews arrived at the scene of the blast three minutes after the call.

"The ambulances were the first to arrive, the first crews were at the scene already three minutes later," she said, adding that "a total of 42 crews worked at the scene."

According to the Minister, "ambulance services operated perfectly."

An unidentified device went off at about 14:40 Moscow time on Monday in a subway train car when the train was moving from Tekhnologichesky Institut Station to Sennaya Ploshchad Station. The Russian Investigative Committee has qualified the blast as a terrorist attack, but other versions are looked into. According to the latest data provided by the National Anti-terrorist Committee, the blast claimed 11 lives. Forty-five people were injured.