One soldier wounded when training helicopter hits roof of four story building in Istanbul’s Sancaktepe district.

Four soldiers martyred, one other wounded when a military training helicopter crashed in Istanbul on Monday, according to the officials.

The helicopter crashed in a residential area in Istanbul’s Sancaktepe district, hitting the roof of a four story building.

The cause of the crash remains unknown, Istanbul Governor Ali Yerlikaya told Anadolu Agency.

The wounded soldier was taken to the hospital.

Security and health teams were dispatched to the crash site.

National Defense Minister Hulusi Akar will also visit the scene for inspections.