A bus headed from Stockholm to Berlin came off a highway in northeastern Germany on Friday and overturned, authorities said. Six people were seriously injured and a further 10 slightly hurt.

Police said the incident happened at about 6.30 a.m. at Linstow, near Rostock, on the A19 highway. Photos from the scene showed the bus lying on its side.

FlixBus, the main operator of long-distance buses in Germany, said the bus was heading from Stockholm to Berlin via Copenhagen, with 63 passengers and two drivers on board. Ferries from Scandinavia arrive in Rostock.

It wasn't immediately clear why the bus left the highway; no other vehicles were involved.