ANKARA, July 5 (Xinhua) -- Seven people were killed and eight others were wounded on Tuesday when a military helicopter crashed in northern Turky, Turkish General Staff said.

The Sikorsky S-70 helicopter, with 15 people on board, crashed in the Tohumluk highlands of the Alucra district of the northern province of Giresun, killing six, including soldiers and their relatives, Turkish General Staff said in a statement on its website, adding that an investigation has been started.

They were returning after the Eid al-Fitr celebrations at military posts and the visits families of fallen soldiers, the statement said.

Turkish Prime Minister Binali Yildirim said earlier on Tuesday that the crash was caused by poor weather.