Baghdad, Iraq (CNN) -- ISIS fighters abducted more than 100 Yazidi women and children from the northern Iraqi town of Sinjar, a senior commander with the group told CNN on Wednesday, a claim that comes amid growing concern over the fate of thousands trapped by the extremists.
The revelation comes as the United States deployed 130 military advisers to get a first-hand look at the humanitarian crisis unfolding as the extremist fighters threaten Iraq's ethnic and religious minorities: Yazidis, Christians and Kurds.
Nowhere is the crisis more evident than the Sinjar Mountains, where an estimated 40,000 minority Yazidis are hiding after fleeing the advance of fighters with the Islamic State, formerly known as the Islamic State of Iraq and Syria, on Sinjar.
The ISIS commander, who has knowledge of the events that unfolded, said the fighters killed a large number of men when they took over the town more than a week ago.
"At that time, they took Yazidi women and children, and I can confirm those women and children have entered Mosul," the commander said by telephone. "...The Islamic State is taking this opportunity to call them to Islam."
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While CNN cannot independently confirm the claim, it follows previous reports by survivors who describe ISIS fighters grabbing families and separating the men from the women and children.
The plight of the Yazidis, coupled with the ISIS assault against Iraq's semiautonomous Kurdish region, prompted the United States to begin targeted airstrikes over the past several days. The aim, according to U.S. President Barack Obama, is to help protect U.S. personnel in the area and to destroy ISIS positions around the mountains to ease the threat to minority groups.
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President Barack Obama ordered nearly 130 advisers to the Kurdish capital of Irbil to assess the humanitarian crisis, and U.S. officials say it's likely that a small number of them will travel to the mountain area to get a first-hand look at what might be possible.
The advisers, made up of Marines and special operations forces, join hundreds of other American advisers already in the country advising Iraqi troops in their fight against ISIS, an offshoot of al Qaeda in Iraq.
The group has waged a brutal campaign while seizing large areas of territory this year in Iraq, aiming to establish a caliphate.