The deadly explosion in St. Petersburg metro in Russia on Monday in which about 10 persons were killed and dozens injured has attracted condolences and umbrage from world leaders . Russian authorities say it was an act of terror, a theory which provides clues of more possible attacks in and around the country which has a history of similar subway attacks.

Secretary General of the Council of Europe Thorbjorn Jagland expressed condolences to Russians over the explosion which killed 10 persons.

“I am shocked and saddened by the news of deadly blasts in St Petersburg. I extend my sincere condolences to our member state Russia,” Jagland wrote on his Twitter page.

Belgian Foreign Minister Didier Reynders offered condolences to the families of the victims.

“I express my condolences to the families of the victims and I think of all the wounded in the explosion in St. Petersburg,” he wrote on Twitter.

Foreign ministers of 28 EU member-states at the meeting of the Council of the European Union are following the news, EU foreign policy chief Federica Mogherini said.

“Following the news coming from Saint Petersburg, together with all EU Foreign ministers, our thoughts are with all people of Russia,” she wrote on her Twitter page.

President of the Parliamentary Assembly of the Council of Europe (PACE) Pedro Agramunt also said on Twitter: “Devastated by news from #StPetersburg, even more so as I was there last week. Terrible tragedy.

My thoughts with the victims & those injured.”

German government spokesman Steffen Seibert wrote on Twitter: “We are receiving terrible news from St. Petersburg. We express condolences to all the victims and their families.”

The United States’ embassy in Russia conveyed its condolences to the families and friends of those killed in the St. Petersburg metro blast, the embassy’s spokesperson Maria Olson said.

“Shocked and saddened by explosions in St. Pete and the resulting deaths and injuries. Our hearts go out to victims and families,” she wrote on Twitter, TASS reports.

Belarusian President Alexander Lukashenko has expressed his condolences to Russian leader Vladimir Putin over a blast in the St. Petersburg metro system.

“I also want to express my condolences to you and convey my condolences to the relatives [of those killed and injured in the metro blast], to St. Petersburg residents who are reacting very painfully and acutely to such things,” the Belarusian president said at the beginning of a meeting with Russian President Putin.

Meanwhile, private transport companies are offering free transportations services to people in St. Petersburg after a blast in the city’s metro.