AMMAN, Jordan — A video released online Tuesday purportedly shows a Jordanian pilot captured by the Islamic State extremist group in Syria last month being burned to death by his captors following a weeklong hostage drama.

The Associated Press was not immediately able to confirm the authenticity of the video, which was released on militant websites and bore the logo of the extremist group’s al-Furqan media service. The 20-minute-long video featured the slick production and graphics used in previous videos released by the group.

Lt. Muath al-Kaseasbeh, 26, fell into the hands of the militants in December when his Jordanian F-16 crashed near Raqqa, Syria, the de facto capital of the group’s self-styled caliphate. He was the first pilot from the U.S.-led coalition battling the group to be captured.

At a tribal meeting place where the pilot’s relatives have waited for weeks for word on his fate, chants against Jordan’s King Abdullah II erupted and some family members wept. An uncle shouted in Arabic: “I received a phone call from the chief of staff saying God bless his soul.”

The pilot’s father, Safi, was surrounded by family members.

Jordanian government spokesman Mohammed al-Momani could not be reached for comment.

Following militant demands, Jordan’s government had said it was willing to trade Sajida al-Rishawi, an al-Qaida prisoner, for the pilot, but that it wanted proof of life first. Al-Rishawi faces death in Jordan for her role in triple 2005 hotel bombings that killed 60 people.

The latest video emerged three days after Japanese journalist Kenji Goto was purportedly beheaded by the militants. The fate of the two captives had been linked but a video of Goto’s purported slaying released Saturday made no mention of the pilot.

An audio message last week, also purportedly from the Islamic State group, only said the pilot would be killed if al-Rishawi was not released Thursday, without actually proposing a swap.

A scroll on Jordan TV said that the pilot was killed on Jan. 3, raising questions over whether any of the hostage negotiations were sincere.

The video included purported images of the pilot showing signs of having been beaten, including a black eye. At the end of the video he is purportedly shown wearing an orange jumpsuit and standing in an outdoor cage. A masked militant lights a line of fuel leading to the cage.

The video also threatened other purported Jordanian pilots.

The Islamic State extremist group, which controls around a third of Syria and neighboring Iraq, has issued a series of grisly videos showing the killing of captives, including two American journalists, an American aid worker and two British aid workers. Tuesday’s was the first to show a captive being burned alive.

Associated Press writers Joseph Krauss in Cairo, Bassem Mroue in Beirut and Karin Laub in Jerusalem contributed to this report.