Updated Feb. 3, 2014 7:46 a.m. ET
MOSCOW—A high-school student burst into a Moscow high school Monday, shooting and killing a teacher and a police officer, briefly taking hostages before being detained by police, officials said.
The incident is a rare case of a school shooting in a country where terrorist attacks are a greater concern.
The teenage student, named by officials as Sergei Gordeyev, entered No. 263 school in northeast Moscow around midday, cocking his gun when a security guard tried to stop him from entering, said an Investigative Committee spokesman.
The security guard managed to press an emergency button before taking the gunman to a biology classroom. On the way, the student shot and wounded a teacher who later died, said spokesman, Vladimir Markin. He then took the class of 20 15-year-olds hostage, officials said.
When police entered the school, a three-story building surrounded by a knee-high green fence, the shooter opened fire, killing one officer and wounding another, officials said. Mr. Markin named the dead policeman as Sergei Bushuyev and the dead geography teacher as Andrei Kirillov.
"We are figuring out the motives. According to out information, Sergei Gordeyev was a straight-A student and most likely had an emotional breakdown," said Mr. Markin.
Police freed the hostages and evacuated the school, a police spokesman told state television. Another police officer was injured during the incident, who was then evacuated by helicopter, officials said.
The shooter fired at least 11 rounds from a small-bore rifle, Mr. Markin said. A police spokesman told Interfax news agency that the rifle and another gun that the student was armed with, a hunting rifle, were registered to his father.
Police wearing helmets and body armor threw up a perimeter around the school, as at least 10 ambulances arrived. There were no reports of injuries other than the wounded police officer. Interior Minister Vladimir Kolokoltsev and Alexander Bastrykin, head of the Investigative Committee, are on the scene.
Education Minister Dmitry Livanov told reporters that the incident could lead to greater security measures in schools.
The Investigative Committee said it had opened a case into kidnapping, murder and attempts on the lives of law enforcers.
Authorities have put law enforcement agencies on high security alert ahead of the Winter Olympic Games in Sochi after bombings late last year in the southern Russian city of Volgograd killed dozens.