It said he has since committed suicide. "The history of Crimea will be divided in two - before and after October 17", the leader of the Moscow-annexed peninsula Sergei Aksyonov told a crowd of hundreds at Kerch's central square.
Numerous victims from Wednesday's attack were teenage students.
The Head of the Republic of Crimea Sergey Aksenov confirmed - while on air on Russian Federation 24 TV-channel - that the college's 4-year student attacked the college.
Investigators are still trying to establish Roslyakov's motive and suggested they are treating it as a school shooting similar to those that have plagued the United States.
It said in a statement that there were around 50 people wounded in the attack.
"There are a lot of victims, they have been loaded into fast cars", a journalist for Kerch FM said.
Witnesses, however, reported that victims were being killed by gunfire.
Russian President Vladimir Putin offered "deep condolences to those who lost their relatives and dear ones as a result of this explosion".
He promised that the government will do everything necessary to help those wounded.
After detonating an explosive device in the canteen, the attacker, named as Vladislav Roslyakov, 18, opened fire on pupils and teachers before killing himself as the security services closed in.
"Vladislav was always telling me about his frequent fights with people around him", she said.
Dozens of soldiers rushed to the school around 12pm local time, suspecting a terrorist attack. He didn't name the man, saying only he was a local resident and was acting alone.
Samuel U. Rodgers hosts 'Crucial Catch' breast cancer awareness event
Also, keep in mind to give yourself regular breast self-exams and get annual breast exams from your doctor after the age of 40. Leslie Aftanas, coalition co-chair, presented a commemorative gift to about 20 breast cancer survivors in attendance.
On Wednesday, Kerch Polytechnic College in the eastern region of Crimea became the site of a horrific mass shooting and explosive attack. The vocational school had only a front desk with no security guards.
Authorities had previously said that it was a lone-wolf attack carried out by an 18-year-old student.
Russian investigators later determined that the victims of the attack were killed by gun shots.
"Everyone ran there. I saw a girl lying there".
The "most of the (victims) are teenagers", the committee said. He did not elaborate.
At least 17 people were killed and 40 injured in the gunfire and the blast, which officials told Reuters went off in the school cafeteria. Russia's National Anti-Terrorism Committee said it had defused a second bomb at the school on Wednesday.
The Investigative Committee said the explosive device rigged with shrapnel went off in the school lunchroom and Sergei Melikov, a deputy chief of the Russian National Guard, said it was homemade.
Earlier, emergency officials said the blast was caused by a gas canister explosion.
Health minister Veronika Skvortsova told journalists that most of those who died suffered gunshot wounds.
Russian Federation annexed the peninsula in March 2014, after a referendum in which the population of Crimea chose to become part of Russian Federation. The college's website says it accepts students in the last three grades of school, from the age of 14.
Crimea was annexed by Russian Federation in 2014 after a controversial referendum, a move that was denounced by the United States and many European countries.