Russia’s Investigative Committee said it has opened a terrorism probe in the case. The blast was caused by an improvised explosive device, Sergei Melikov, first deputy head of the National Guard, said, according to the state-run Tass news service. The comments went further than an earlier statement by President Vladimir Putin’s spokesman, Dmitry Peskov, who said the possibility of terrorism “is being considered.”

The blast at the Kerch Polytechnic College wounded around 50 in the city of Kerch, near the eastern end of the peninsula that Russia annexed from Ukraine in 2014, the Investigative Committee said. The shrapnel-filled bomb went off in the cafeteria around lunchtime, killing mostly adolescent students. The death toll is likely to rise further, Irina Kluyeva, Crimea’s ombudsman for children’s issues, said, according to Interfax.

Putin ordered the Federal Security Service to investigate the explosion.

Kerch is the landing point and namesake of a bridge that opened earlier this year to connect Crimea to Russia. Security on the bridge was tightened after the attack, RIA Novosti reported.

Russia has suffered a number of deadly terror attacks in recent years, as well as shootings by students at schools.

The most recent major attack in Russia killed 14 people in a suicide bombing by an Islamic extremist in the St. Petersburg subway last year. Russia has nearly 50 Crimean natives on its list of terrorists, although some human rights groups claim that the inclusion of many of them is politically motivated. DM