MOSCOW, April 3. /TASS/. MOSCOW, April 3. /TASS/. Moscow metro authorities have beefed up security after a blast rocked St. Petersburg’s metro.

"The Moscow metro is taking additional security measures according to federal legislation on Russia’s transport security," a statement posted on the Telegram social network said.

"Authorities of the Moscow metro are ready to provide any assistance to the St. Petersburg metro if needed," it said.

According to preliminary information, ten people were reported killed by an explosion inside a subway train that had pulled into the Sennaya Square station in St. Petersburg, emergency services told TASS.