Two people were killed in a "violent incident" at a school near Berlin, local media reported on Thursday, saying an 18-year-old woman student and a 30-year-old man had died.
Regional public broadcaster RBB and a local daily said the alarm had been raised at a secondary school in the town of Gosen-Neu Zittau, just outside the German capital.
The Märkische Allgemeine newspaper reported online that the man arrested was 19 years old and the ex-boyfriend of the victim.
It said the 30-year-old man died while trying to intervene, without specifying whether a weapon was used or whether other people were injured.
Police earlier confirmed only that two people had suffered severe injuries, that they were on the scene and that a suspect had been arrested.
Images from the streets near the privately run secondary school showed an ambulance and many other emergency service vehicles, while rescue helicopters were deployed.
Last month, two girls were seriously wounded and a 16-year-old suspect arrested after an attack at a secondary school in southern Germany.
Authorities said at the time that the suspect in that attack had been suffering a "mental health emergency".
This is a developing story and our journalists are working on further updates.
