A teenage Afghan refugee armed with an axe and knife injured four people on a train in southern Germany before being shot dead by police, officials say, the BBC reports.
Three people in a group from Hong Kong were seriously hurt and one slightly injured in the attack in Wurzburg. Another 14 were treated for shock.
Bavarian Interior Minister Joachim Herrmann said the attacker was killed as he tried to flee the scene.
The motive for the attack is not yet clear.
The South China Morning Post said it was believed the four injured were a 62-year-old man, his 58-year-old wife, their daughter, 27, and her boyfriend, 31. The 17-year-old son travelling with them was not hurt, it said.
A source told the paper the father and boyfriend had tried to protect the other members of the group.
Mr Herrmann said the attacker was a 17-year-old Afghan refugee who had been living in the nearby town of Ochsenfurt.
He told public broadcaster ARD that the teenager appeared to have travelled to Germany as an unaccompanied minor.