The Islamic State group released more than 200 mostly elderly members of northern Iraq's Yazidi minority on Saturday who had been held for months, officials said.

The Yazidis were freed on the front line southwest of the city of Kirkuk and met by Kurdish peshmerga forces who brought them to a health center in Altun Kopri, on the road to the Kurdish regional capital of Arbil.

"These men and women had been held in Mosul," Khodr Domli, a leading Yazidi rights activist, said at the center. "We already have names for 196, and there could be some more.

"Some are wounded, some have disabilities and many are suffering from mental and psychological problems," he said.

Dozens of Kurdish doctors and nurses provided emergency care at the Altun Kopri health center, where Yazidis who had heard the news started to mass at the gates, hoping to be reunited with missing relatives.

"We have dispatched laboratory teams to check their blood, to control for things such as polio and possible contagious diseases," said Saman Barzanji, director general of the Arbil health department.

Those freed, some in wheelchairs, others leaning on walking sticks, looked tired and distraught as they waited to give blood samples.

Officials said the mass release, the largest of its kind, took them by surprise.

"IS must have decided that they could no longer feed them and look after them. They were a burden," Domli said.

"IS saw that there was no benefit for them in keeping these old people," said Vian Dakhil, a member of the Iraqi parliament.

AFP - AP