At least 15 people are dead, another two dozen are wounded after a gunman shot up a school in central Russia. Early reports indicated the gunman was inspired by the shooters behind the Columbine High School massacre.

The shooting took place at a school in Izhevsk, a city about 600 miles east of Moscow. Police said the 34-year-old gunman entered the school Monday wearing all black clothing and a black mask. Police said the shooter, who was a graduate of the school, had a red Nazi swastika painted on his shirt and was armed with two pistols.

The guns were designed to be non-lethal, but authorities said they were modified to shoot real bullets. The pistols had braided key chains with the words “Columbine,” “Eric” and “Dylan” on them. Eric Harris and Dylan Klebold were the names of the two Columbine shooters.

The gunman also had multiple magazines of extra ammunition with the word “hatred” written on the side. Police said the gunman killed himself.

At least 15 people are dead, including 11 children. Another 24 are wounded. One local politician called the attack a “terrorist act.”

A spokesperson for the Kremlin said President Vladimir Putin “deeply mourns the deaths of people and children in the school.” Russia has seen several school shootings in recent years. An investigation into the most recent incident has been launched.

The Associated Press contributed to this report.