Iran prison abuse exposed by hackers' CCTV leak
The head of Iran's prison service has apologised after hackers leaked videos showing the abuse of detainees at Tehran's Evin prison.
Many political prisoners and foreigners are held at Evin.
Hackers released CCTV footage in which guards are seen beating prisoners and dragging one on a floor.
Mohammad Mehdi Haj-Mohammadi said he took responsibility for the "unacceptable behaviour".