An assailant has killed a teacher at a school in the western German city of Ludwigshafen, police say.
Police have evacuated the school and arrested a 23-year-old suspect, German media report. The incident happened at about 1000 local time (0900 GMT).
Some reports say several teachers were attacked in a "rampage". It is not yet clear what weapon was used.
The vocational school in the Mundenheim district has more than 3,200 pupils. It has been sealed off by police.
There are reports the attacker used a knife, but witnesses said they also heard shots.
It is still unclear if others have been injured, but German television showed footage of students calmly evacuating the school.
The premises have been searched by police. Normally 130 teachers work there. It is one of the biggest vocational schools in the region.
Last March a heavily armed 17-year-old killed 15 people by opening fire on pupils and teachers at his former school in Winnenden, south-west Germany. He shot himself dead after being cornered by police.
Another teenager, wielding an axe, knives and petrol bombs wounded nine children last September at a school in south Germany.
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