At least 18 people were killed, most of them teenagers, and about 50 more injured following a bombing in Russian-annexed Crimea, according to Russia.

Russia's National Anti-Terrorism Committee told CNN in a statement that the blast was caused by an “unidentified explosive device” at a college in the city of Kerch, where a new 19-kilometre bridge links Crimea to Russia.

Russia's Investigative Committee said in a statement: “According to preliminary data, an unidentified explosive device packed with metal objects went off today in the dining room of the Kerch Polytechnic College.”

It said information on the victims is being clarified and that “most of them are teenagers.”

Sergey Aksyonov, the head of the Crimean government, said the suspected perpetrator of the attack had taken his own life, according to remarks carried on Russian state television. “The alleged killer shot himself dead, committed suicide,” Aksyonov told Rossiya-24, adding that the suspect was a student at the same educational institution and that his body was found in a library on the second floor.

Kremlin spokesperson Dmitry Peskov said Wednesday that the possibility that this was a terror attack “is being considered.”

“The President has instructed the Ministry of Health and Emergency Services Ministry to take emergency measures to assist victims of this explosion, if necessary, to ensure the urgent transportation of seriously wounded patients to leading medical institutions of Russia, whether in Moscow or other cities,” Peskov said.

Russian state media, quoting emergency-services officials, reported earlier that a suspected gas explosion at a technical college claimed several lives and injured dozens of people.

State television channel Rossiya-24 said 200 military personnel had been sent to the site of the incident. Crimea, a peninsula south of Ukraine, which is surrounded by the Black Sea and the Sea of Azov, was annexed by Russia from Ukraine in 2014. Aksyonov announced on Russian state TV there would be three days of mourning.