WINNENDEN (Agencies) - A teenager in black combat gear went on a rampage at his old school in Germany Wednesday, slaying at least 15 people before turning his gun on himself during a shootout with police. Nine children - eight of them girls- three teachers and three passers-by were mown down by the teenager, who was then killed in a firefight in which at least two policemen were also injured. The 17-year-old, named as Tim Kretschmer, entered the secondary school in Winnenden near Stuttgart at 9:30 am (0830 GMT), killing nine pupils aged between 14 and 15 and three teachers in different classrooms with a handgun. He wandered into several classrooms at the school he left last year, indiscriminately spraying bullets at teachers and students. "He was constantly reloading his weapon," local police chief Konrad Gelden told reporters. "He just opened the door, pulled out his gun and started shooting," one pupil said on German television. "One person saw someone shot in the head." "My brother was in the classroom in which it happened," said another. "He was sitting next to his girlfriend and she was shot." A teacher threw herself in front of a female pupil - and was shot by the gunman, Bild said. Police were alerted to the shootings within three minutes and despatched two vehicles to the scene where they discovered the bodies of the pupils and three teachers - one of whom had only been working at the school for four weeks. The 17-year-old then fled the Albertville-Realschule and went to a nearby psychiatric clinic where he shot dead a member of staff and stole a Volkswagen Sharan car. He then sped 40km to the town of Wendlingen. Cornered in the car park of a shopping centre, a shootout between the teenager and the police ensued, in which two passers-by were killed. Kretschmer turned his gun on himself after being wounded in the shootout, police said. "According to the latest police information, he was hit in an exchange of fire (with police) and then used his weapon on himself," police spokesman Fritz Mehl told AFP. Two policemen were seriously injured in the firefight but they were in a stable condition in hospital. Eight people were injured altogether. Some police officers said he shot himself dead after being wounded by the police. German Chancellor Angela Merkel expressed her condolences to the families and friends of those killed in what she called a "horrendous crime." "Like all people in Germany, I find what happened today in the Albertville-Realschule in Winnenden incomprehensible," Merkel said. "It is a day of mourning for the whole of Germany. Our thoughts go out to the families, the friends. We are thinking of you and we are praying for you," Merkel added.