The Islamic State in Iraq and Syria (ISIS) group strung up four Iraqi Shiite fighters with chains and burned them alive, according to footage posted online, the latest gruesome execution video from the militants.
The victims - identified as fighters in the pro-government Popular Mobilisation forces from southern Iraq - were suspended from a swingset-like metal structure by chains attached to their hands and feet, then set on fire.
ISIS, which overran large parts of Iraq last year and still controls much of the country's west, said the murders were in revenge for the alleged burning of four men by pro-government forces.
"Now retribution has come, for today, we will attack them as they attacked us, and punish them as they punished us," a masked militant says in the video.
The video was not dated and did not give a specific location for where the killings took place, but it did carry a tag indicating that it was produced by the ISIS media unit responsible for Iraq's Anbar province.