ZURICH (Reuters) - Two 14-year-old boys and a pilot died on Friday when their single-engine plane crashed into a Swiss mountain during a summer camp flight for young aviation enthusiasts, police said.

A 17-year-old female camper was badly hurt in the crash in the eastern canton of the Grisons. The cause was still under investigation.

“When I heard about the terrible accident this morning my world was shattered,” camp director Yves Burkhardt told reporters, adding the sightseeing flight at week’s end was supposed to be a highlight for nearly 200 young people at the holiday camp that had operated without incident for 35 years.

Authorities said the four-seat Piper aircraft, on its second flight of the day and under the control of an experienced pilot, crashed in the Diavolezza region around 10 minutes after take-off.