A BUS carrying school pupils to a ski resort has crashed in central Sweden, killing three people and injuring 20 others.

Seven of the injuries are reported to be serious, rescue officials said.

Prime minister Stefan Lofven said the accident "leaves me and the whole country in sorrow".

The 52 students were en route to a ski resort with seven adults, including the driver, when the accident occurred.

It happened on a main road south of Sveg, a small town 260 miles from capital Stockholm.

The father of Stina Almqvist, one of the students on the bus, said he was woken by a call from his "panic-stricken" daughter.

"She just screamed and screamed," Fredrik Almqvist told the Expressen tabloid. "I can still hear her screams."

The cause of the accident was not immediately known but the road was reported to be icy when the accident occurred at about 7am local time.

Pictures showed the bus lying on its side in a ditch beside the road.

Rescue services spokesman Peter Nystedt said some 30 other people sustained minor injuries.

Friends of the students, from Angskolan high school in Skene, gathered at the school on Sunday.

A priest from a nearby church, Goran Landgren, told reporters at the school that the accident had "deeply upset them all".