MOSKOW –Twin blasts occurred in metro stations of St. Petersburg and at least 10 people lost their life and 20 were wounded.

At least 10 people were killed in explosions in two train carriages at metro stations in St. Petersburg, authorities said.

Russian President Vladimir Putin, who is in St. Petersburg for a meeting with Belarussian leader Alexander Lukashenko, said the cause of the blasts was not clear and efforts were underway to find out. He said he was considering all possibilities including terrorism.

It was also reported that three stations have been closed, according to Reuters’ news.