Cairo - Kurdish forces have in recent weeks discovered nine mass graves containing members of Iraq's Yezidi minority believed to have been executed by Islamic State militants in the north-western town of Sinjar, a Kurdish official said on Tuesday.

“The graves contain the remains of Yezidi victims killed by the terrorist Daesh insurgents,” said Khairy Buzani, in charge of Yezidi affairs in the autonomous region of Kurdistan, using an Arabic acronym for the radical group.

The graves were found in areas in the mostly Yezidi town of Sinjar recently retaken by Kurdistan's Peshmerga forces from Islamic State militants, state-run broadcaster al-Iraqiya TV quoted Buzani as saying.

The official did not give details as to how many people had been buried in the graves.

Earlier this month, the Peshmerga broke a months-long siege by Islamic State militants on Mount Sinjar and pushed deep into the town located at the foot of the mountain.

Islamic State fighters have destroyed 18 Yezidi temples since the extremist Sunni militia launched an incursion in northern Iraq in June, Buzani said.

The Islamic State group regards Yezidis, followers of an ancient faith, as devil-worshippers.

The Peshmerga are seeking to fully recapture Sinjar in an attempt to cut off a main supply route for jihadists between the Syrian border and Mosul, Iraq's second-largest city.

The al-Qaeda splinter group has controlled Mosul since June. It also controls considerable territory in neighbouring Syria.

Last week, the jihadist group captured a Jordanian pilot after his jet crashed while on a bombing mission near Syria's north-eastern province of al-Raqqa.

In the first images since his capture released late Monday, the pilot, Moaza al-Kassasbeh, is clad an orange jumpsuit, a uniform worn by hostages shortly before they are executed by Islamic State militants.

The militia's latest edition of its Dabiq magazine featured what the group claimed to be an interview with the 26-year-old, who said his plane had been brought down by a heat-seeking missile.

Al-Kassasbeh is the first known allied serviceman to have been taken hostage by the Islamic State since the United States and Arab allies started an aerial campaign against the extremist group in Syria in September. - Sapa-dpa