DIYARBAKIR: Thousands of Iraqis, predominantly from the minority Yazidi ethnic group, have fled to the Turkish border to escape an advance by Islamic State fighters in northern Iraq, local officials said on Thursday.

Around 150 Yazidis were placed in state residences in Turkey's southeastern Sirnak province and around the nearby city of Batman after crossing the Habur border gate late on Wednesday, the officials said.

“Those who have passports crossed the border, but thousands of people who don't are waiting at the other side,” said Seyfettin Aydemir, the mayor of Sirnak's Silopi district.

“We're in talks with regional lawmakers about the situation,” he said.

Islamic State militants extended their gains in northern Iraq on Thursday, seizing more towns and strengthening a foothold near the Kurdish region in an offensive that has alarmed Baghdad and regional powers.

Turkey, already housing more than a million refugees from the war in neighbouring Syria, is building a refugee camp in northern Iraq to try to provide aid on the Iraqi side of the border.

The Islamic State regards the Yazidis, followers of an ancient religion derived from Zoroastrianism and part of the Iraq's Kurdish minority, as “devil worshippers”, making them prime targets for the militants.