As many as 180,000 people have fled fighting between Iraqi forces and Islamic State (IS) militants in and around the city of Hit in western Anbar province, the UN said, according to BBC News.

The civilians - many of whom were already displaced - have headed east towards the war-torn city of Ramadi.

The UN says the refugees are in need of food, blankets and medical supplies.

IS captured Hit earlier this month in an advance across Anbar that has alarmed Iraqi leaders. Analysts say seizing Anbar would enable IS to establish a supply line to launch possible attacks on the Iraqi capital, Baghdad.

Meanwhile, an article in IS's online magazine Daqib said that Yazidi families have been sold into slavery by the group.

The Yazidi people lived in an area of north-west Iraq overrun by IS fighters in August.

The article says the people were divided among IS fighters "according to Sharia law" and goes on to describe slavery as a type of pathway to Islam.

A recent Human Rights Watch report said IS had systematically separated captured women and girls from their families and forced some to marry its fighters.

Reports of atrocities have also come from the northern Syrian town of Kobani where IS fighters are battling Kurdish forces.

Witnesses have reported IS fighters beheading civilians trying to flee to safety.

Kurdish forces say they urgently need more weapons and ammunition to push back the militants' advance in the town.