Updated

Hundreds of women from the Yazidi religious minority have been taken captive by Sunni militants with "vicious plans," an Iraqi official said Friday, further underscoring the dire plight of Iraq's minorities at the hands of the Islamic State group.

Kamil Amin, the spokesman for Iraq's Human Rights Ministry, said hundreds of Yazidi women below the age of 35 are being held in schools in Iraq's second largest city, Mosul. He said the ministry learned of the captives from their families.

"We think that the terrorists by now consider them slaves and they have vicious plans for them," Amin told The Associated Press. "We think that these women are going to be used in demeaning ways by those terrorists to satisfy their animalistic urges in a way that contradicts all the human and Islamic values."

The U.S. has confirmed that the Islamic State group has kidnapped and imprisoned Yazidi women so that they can be sold or married off to extremist fighters, said a U.S. official who spoke on condition of anonymity because the information came from classified intelligence reports. There was no solid estimate of the number of women victimized, the official said.

Tens of thousands of Yazidis fled when the Islamic State group earlier this month captured the northern Iraqi town of Sinjar, near the Syrian border. The Yazidis practice an ancient religion that the Sunni Muslim radicals consider heretical.

The extremist group's capture of a string of towns and villages in the north has sent minority communities fleeing for their lives. The Islamic state views Yazidis and Shiite Muslims as apostates, and has demanded Christians either convert to Islam or pay a special tax.

About 50,000 Yazidis — half of them children, according to U.N. figures — fled to the mountains outside Sinjar where many of them remain, trapped and running out of food and water. Late Thursday, the U.S. military cargo jets dropped humanitarian aid to the mountains.

Amin's comments were the first Iraqi government confirmation that some women were being held by the group. On Tuesday, Yazidi lawmaker Vian Dakheel made an emotional plea in parliament to the Iraqi government to save the Yazidi people, saying the "women have been sold in a slavery market."

President Obama said the humanitarian airdrops were made at the request of the Iraqi government as the Islamic State militant group tightened its grip on northern Iraq. In his remarks late Thursday, he mentioned "chilling reports" of fighters with the group "rounding up families, conducting mass executions, and enslaving Yazidi women."