The UN has warned that up to 200,000 people have been forced to flee their homes after militants took over more towns in northern Iraq.

Islamic State (formerly known as Isis) militants are reported to have taken over the town of Sinjar near Syria.

It follows the IS takeover of the town of Zumar and two nearby oilfields from Kurdish Peshmerga forces on Saturday.

IS seized large parts northern Iraq from government control in a major offensive in June.

The UN special envoy to Iraq, Nickolay Mladenov, said that a "humanitarian tragedy is unfolding in Sinjar".

"The United Nations has grave concerns for the physical safety of these civilians" he said.

"The humanitarian situation of these civilians is reported as dire, and they are in urgent need of basic items including food, water and medicine" he added.

The UN said many of those who fled are in exposed areas in mountains near the town.