Kurdish Iraqi officials on Friday condemned a video depicting the beheading of one of their soldiers by Islamic State extremists, who said it was retribution for the Kurds' alliance with the United States.
The six-minute video shows 15 Kurdish soldiers held captive in the militant-held city of Mosul, one of whom is later killed in front of a mosque.
Kurdish officials said they were treating the video as authentic but that it would not deter their forces from battling Islamic State, a Sunni Arab militant organization that has claimed a caliphate on lands it controls in Syria and Iraq. Kurdish soldiers backed by U.S. airstrikes have pushed the extremists out of some of the territory they seized this month in an offensive across parts of northern Iraq.
"We have lost many men, and maybe we will lose more men, but that will not stop us from implementing our strategy," said Ari Mamshae, a spokesman for Massoud Barzani, president of Iraq's semiautonomous northern Kurdish region.
The video, which was posted to YouTube on Thursday but immediately deleted by the site, is part of a propaganda effort by Islamic State that has drawn international condemnation. A similar video circulated last week showing the killing of American journalist James Foley, who was captured in Syria two years ago.
A member of Islamic State also claimed Thursday to have beheaded one of 11 Lebanese soldiers the group captured this month in clashes along the Syria-Lebanon border.
A Twitter user named Abou Misaab Hafid al-Baghdadi linked to a picture showing the soldier's beheading with the message, "Now you know who are the lions of ISIS," an acronym sometimes used for Islamic State. Lebanese officials reportedly were investigating whether the claim was authentic.
The video from Iraq showed the Kurdish soldiers wearing orange jumpsuits, as did Foley. One soldier named Hassan Mohamed Hashin read a message to Kurdish leaders that said, "You have made a big mistake by joining hands with America."
Later in the video, a black-clad militant brandishes a knife next to a soldier as he warns that the rest of the captives will be killed if Kurdish forces don't break their alliance with the U.S. The next clip shows the soldier's bloodied body.
Working with the U.S. military, Kurdish forces have rolled back some of Islamic State's territorial gains. The Pentagon has carried out 110 airstrikes in Iraq this month, more than half in the area of the strategic Mosul dam, including four on Friday that targeted militant vehicles.
The Kurdish soldiers known as peshmerga, who retook Mosul dam two weeks ago, reportedly drove the militants out of the northern district of Zumar on Thursday amid clashes that left several civilians dead or injured, residents said.
In recent weeks, Kurdish commanders have met with teams of U.S. military advisers and have said they expect to receive weapons and ammunition from the United States to help fight the well-armed militants.
Special correspondent Nabih Bulos in Amman, Jordan, contributed to this report.