Iraqi forces recaptured a prison northwest of Mosul where the Islamic State group reportedly executed hundreds of people and held captured Yazidi women, the military said on Wednesday.
Iraqi special forces units are spearheading the operation to retake west Mosul, which began on February 19, while soldiers and pro-government paramilitaries are fighting IS in areas outside the city.
Forces from Iraq's 9th Armoured Division and the Furqat al-Abbas paramilitary group recaptured Badush prison, Iraq's Joint Operations Command said in a statement.
It did not specify whether anyone was still being held inside the prison when it was retaken.
According to Human Rights Watch, IS gunmen executed up to 600 inmates from Badush prison on June 10, 2014, forcing them to kneel along a nearby ravine before pushing them in and setting fire to the bodies.
And Iraqi lawmaker Vian Dakhil said that year that the jihadists were holding more than 500 Yazidi women at Badush.
IS targeted the Yazidi religious minority in a brutal campaign of executions, kidnapping and rape, killing men and holding women and girls as sex slaves.
The jihadists overran large areas north and west of Baghdad in 2014, but Iraqi forces backed by US-led air strikes and other support have since recaptured most of the territory they lost.
Iraqi forces launched an operation to retake Mosul on October 17, recapturing the eastern side before setting their sights on the smaller but more densely populated west.