Four Isis jihadists beheaded in revenge killing by Afghan fighters

The beheadings happened after Isis made inroads into the Afghan province

An Afghan militia man stands guard in the Achin district of Nangarhar province east of Kabul, Afghanistan, Sunday, Dec. 27, 2015. (AP)

Four Isis fighters have been reportedly decapitated and had their heads put on display by the side of a road in a revenge killing by Afghan militia.

Militants loyal to a powerful Afghan lawmaker placed the severed heads of their opponents on the side of the main road in Nangarhar, in eastern Afghanistan, local officials said on Sunday.

The killings highlight the increasingly brutal violence of the fight between Isis and rival groups as they engage in a bitter power struggle in the region.

Opposing forces include the Afghan National Army, local militias defending their territory, the Taliban, and Isis - the latter of which claims to be annexing the nation to its so-called caliphate across Syria and Iraq.

An Afghan official says fighters for the Islamic State group and a militia controlled by a prominent lawmaker have beheaded a total of eight men in tit-for-tat revenge killings in the eastern border province of Nangarhar. (AP Photo/Mohammad Anwar Danishyar) (AP)

Dozens of members of a local militia force who are loyal to Haji Zahir, the deputy speaker of parliament, have been battling both Taliban and Isls fighters in the district for weeks, after the jihadist group made inroads into the province.

Isis fighters first captured four fighters from the militia, known as Pasoon or "Uprising", and beheaded them. The militias then retaliated, Zahir told reporters.

"Do you think if they behead you, you cook them sweets?" Zahir asked.

Ataullah Khoqani, a spokesman for the provincial governor, said Afghan government forces were not involved in the incident and that the incident is being investigated.

In a sign of Isis's growing reach, its fighters have taken to the airwaves in a radio show called "Voice of the Caliphate" in Nangarhar to win recruits among young Afghans.

Last week, local authorities said they had blocked the broadcast but Zahir said the 90-minute daily Pashto language broadcast was still operational.

Isis is a relatively new force in Afghanistan and there is some dispute about how strong it is, how many members it commands and how closely they are linked operationally to the movement's main arm in Iraq and Syria.

Last week, the commander of international forces in the country, US general John Campbell, said there were between 1,000 to 3,000 members of the Isis movement in Afghanistan and he said its influence would spread if left unchecked.