CAIRO (Reuters) - Libya officials should investigate and dismiss forces involved in atrocities, a human rights group said on Monday, after a video appeared on social media purportedly showing a military unit executing 20 suspected militants.

The video was seen by Reuters on social media but it could not be independently verified. It appears to show a military unit linked to eastern commander Khalifa Haftar executing 20 hooded men they accuse of being Islamic State militants found guilty of bombings and killings.

The video is the latest that appears to show Haftar’s Libyan National Army troops engaged in summary executions of suspected militants. An LNA spokesman in Benghazi declined to comment on the video but it has previously denied its forces are involved.

“This latest mass execution, if confirmed, would be one more in a string of atrocities committed by members of the Libyan National Army forces and is yet another manifestation of how its members are taking the law into their own hands,” Eric Goldstein, Middle East and North Africa deputy director for Human Rights Watch, said.

The video was released in a week when Haftar and Fayez al-Serraj, the leader of Libya’s U.N.-backed government, are due to meet French President Emmanuel Macron in Paris for talks over a political agreement to end the factional fighting.

Haftar and his allies have rejected the authority of Serraj’s government in Tripoli that is supported by other armed factions and presented by Libya’s Western partners as the solution to the country’s crisis.

POWER STRUGGLE

Haftar’s LNA is one of the most powerful military forces in the country, gaining ground in the east and the south with the support of Egypt and United Arab Emirates who back his campaign against Islamist militants.

Libya has had no national army, despite the name of Haftar’s group, since the fall of Muammar Gaddafi in a 2011 civil war sent the state spiralling into a power struggle among competing brigades of former rebels each backing rival political factions.

Goldstein said the LNA and the Libyan government needed to remove from duty those accused of violations and hold them accountable if found guilty after a transparent investigation.

“A failure to do so risks implicating senior military commanders in these apparent war crimes,” he said.

The video purports to show an LNA commander reading out a statement before rows of men kneeling in orange jumpsuits with black hoods over their heads and their hands bound. LNA forces move row by row to fire into the back of their heads and bodies.

“Executed by firing squad after they were found guilty,” a caption on the video reads.

The video did not explain how the men had been found guilty, but armed groups in Libya often say they are legitimate forces that carry out their own investigations, and have been accused of torturing and abusing prisoners.

An LNA special forces commander, Mahmoud al-Werfalli, appears in the video. The United Nations has previously called for the LNA to dismiss him after a video in March allegedly showed al-Werfalli shooting dead three men who were kneeling and facing a wall with their hands tied behind their backs.

In June, two further videos appeared to show summary executions carried out by LNA fighters on his orders.

Earlier this month, the U.N. human rights body called on the LNA to investigate summary executions of prisoners and torture of those still in captivity. In March, the LNA said it would investigate potential war crimes but has not released any details of the probe.

The U.N. human rights office had no immediate comment about the latest video.