Zabul’s police chief Mirwais Noorzai said the Afghan National Army helicopter crashed into a remote region in the province, on Thursday.
He added that five of those killed were pilots while the remaining 12 were soldiers.
The incident is the worst suffered by the Afghan military since US-led forces formally ended their combat mission in the country last December, handing security control to Afghan forces.
The cause of the crash remains unknown and an investigation is currently underway.
The Taliban militants have been carrying out attacks in the southern province of Zabul in recent months. In May, the militants targeted a government complex and later attacked a number of police posts in July.
The deadly incident comes as recent reports suggest that the Taliban’s long-time leader Mullah Omar, whose death was recently confirmed by the group, was buried in Zabul. The Taliban has since been surrounded by reports of growing divisions among its members.
The crash comes on the same day Taliban militants claimed responsibility for a bombing attack near a provincial council office in Logar Province, which claimed the lives of at least eight people.