Libyan jihadist militants affiliated with ISIS beheaded a young soldier and posted the video online Thursday, the fourth such beheading carried out this week in the country.

The video was posted online by the “Father of the Injustice Battalion,” part of Ansar al-Sharia, a militia designated by the U.S. as a terrorist group, according to The Times of London. The group is fighting pro-government forces under General Khalifa Hiftar for control of Benghazi.

The video shows Ahmed Muftah el-Nazihi, a soldier who was fighting with Hafter’s Operation Dignity Forces, saying to the camera: “I advise those who were with me ... to leave these activities and go back to their houses or they will face the same destiny: beheading.”

He is then brutally beheaded with a knife, and his head is placed on his body, according to a report from the Libya Herald. A message introducing the clip says that the beheading is a retaliation to military actions carried out by Haftar's Operation Dignity forces.

The killing is the fourth such murder in Libya this week, after the beheaded remains of three young activists from Derna were discovered Tuesday. Siraj Ghatish, Mohamed Battu and Mohamed al-Mesmari had posted information about what was taking place in the city on social media, and were kidnapped by militants earlier this month, according to the BBC.

Derna is now reportedly under the control of the Islamic Youth Council, a branch of the al Qaeda-inspired Ansar al-Sharia, who have pledged loyalty to the Islamic State group, or ISIS, carried out public executions in the town and engaged in battles with other militant groups that have resulted in civilian deaths.

Libyan fighter jets reportedly carried out air strikes on Derna Wednesday, targeting militant groups who are fighting to wrest control of the city, according to a report form Al Arabiya.

A BBC correspondent in the city says that three militant groups are fighting to control Derna, the Islamic Youth Shura Council, the more moderate Martyrs of Abuslim Brigade, and a group that broke away from the Shura Council.