MOSCOW, April 3. /TASS/.  All metro stations in St. Petersburg have been closed following the blast at the Sennaya Ploshchad subway station.

More than 80 rescue workers have been dispatched to the St. Petersburg metro’s explosion site, a source in the regional center of the Russian Emergencies Ministry told TASS.

"Over 80 people, as well as 16 units of equipment, have been involved in the clean-up operation," the source said.

According to him, the number of rescue workers may be doubled to 120.