At least 10 people have died and many more wounded after a explosion at a college in Crimea.
The blast was initially thought to have been caused by a gas canister but Russia's anti-terror agency, the National Anti-Terrorism Committee (NAC), said an "unknown explosive device" was used.
Students in the Crimean college where at least 17 people died on Wednesday (Oct 17) said they heard shooting and chaos as students fled from a gunman or multiple gunmen in the building.
Law enforcement officials said they were treating the incident as a terror attack.
The bomb blast took place in the city of Kerch, which is the entry point for a new 19km bridge linking Crimea to mainland Russian Federation. He told Russian state television that a single suspect, a 22-year-old male student of the college, killed himself after the alleged attack.
Numerous victims from Wednesday's attacks were teenage students who suffered shrapnel and bullet wounds.
The committee's spokesman Andrei Przhezdomsky said sappers are inspecting the building for other explosive devices.
Presidential spokesman Dmitry Peskov said President Vladimir Putin ordered agencies, .
Kerch is the landing point and namesake of a bridge that opened earlier this year to connect Crimea to Russian Federation.
"A strong explosion went off, but thank God, I was already outside and saw our guys being thrown out of the windows by the explosive wave", said one student.
It said around 50 people were wounded, many of whom were teenagers.
Crimea has been under Russia's control since Moscow sent troops to seize the peninsula from Ukraine in 2014.
"After 10 minutes police with automatic rifles arrived", he said.
"There are already lots of people in the emergency room, and in the operating theater", a school employee told Tass.
The head of Crimea, Sergei Aksyonov, and Russia's health minister, have headed to the area.