Several people have been killed in a shooting at a university in the Russian city of Perm.
A gunman opened fire, sending lecturers and students fleeing into classrooms where they locked themselves in, the TASS news agency reported.
Russia's Investigative Committee, the agency that handles major crimes, said the gunman had been identified as a student at the university.
It originally put the death toll at eight but later revised it to six. Reports suggest up to 28 victims sought medical help, some of whom were rushed to hospital.
Perm State University’s press service told Reuters that the gunman is in his teens.
Initial reports suggested he had been killed. However, the Investigative Committee said he is being treated in hospital.
Video footage captured at the scene showed people jumping from first-floor windows to escape the building.
Students could be seen throwing their belongings out of windows before jumping out on to a pavement and grassy area.
An unverified video posted on social media purporting to be of the attacker showed a man dressed in black and wearing a helmet walking towards the university while carrying a weapon.
There was no immediate information on the gunman’s identity or possible motivation.
Russia has strict restrictions on civilian firearm ownership, but some categories of guns are available for hunting, self-defence or sport, once would-be owners have passed tests and met other requirements.
Another clip showed a pavement smeared with blood and a group of people attending to an injured man, who lay on the ground.
The victim appeared to be bleeding heavily from a leg wound.
Photos showed people hugging each other outside the university.
A source told TASS: "On Monday, an unidentified person entered the university building and opened fire.
“Some students locked themselves in the university's auditoriums to hide from the attacker. Some students jumped out of the windows.
“Law enforcement agents are heading to the site.”
Perm is about 1,150 kilometres east of Moscow, with a population of about one million. The university has about 12,000 students.
In May, a gunman opened fire at a school in the city of Kazan, killing seven students and two teachers.
