Mahmoud al-Werfalli commands the Al-Saiqa Brigade based in Libya’s second city and is loyal to military strongman Khalifa Haftar whose forces dominate the east of the North African country.
When the ICC issued a warrant for Werfalli’s arrest last August over summary executions in which at least 33 people were killed in 2016 and 2017, Haftar’s forces insisted he was in their custody and would face a military trial.
But video and photographs posted on social networks on Wednesday appeared to show him personally putting bullets to the heads of 10 prisoners at the site of deadly twin bombings in Benghazi the previous day.
Witnesses said that Werfalli had carried out the public executions of the suspected jihadists in revenge for the Tuesday attack, which killed at least 37 people outside a mosque in the heart of the city.
In the video, a uniformed officer, said to be Werfalli, is seen making the blindfolded suspects in blue prison uniform kneel in front of him before shooting them one after the other.
Their bodies are then thrown on the back of a pickup truck to applause from the crowd.
In a statement, the UN Support Mission in Libya said it was “alarmed by reports of brutal and outrageous summary executions in Benghazi”.
“UN demands the handing over of Mahmoud al-Werfalli immediately to the ICC in The Hague as it documented at least five similar cases, in 2017 alone, carried out or ordered by Werfalli,” the mission said on Twitter.
The latest executions came as UN envoy Ghassan Salame was in eastern Libya for talks with Haftar as part of his efforts to end the political chaos that has gripped the country since longtime dictator Moamer Kadhafi was ousted and killed in a NATO-backed uprising in 2011.
A UN-backed unity government based in the capital Tripoli has struggled to assert its authority outside western Libya. Haftar supports a rival administration based in the east.
Salame presented a plan to the UN Security Council in September to hold fresh parliamentary and presidential elections later this year, but analysts are sceptical they will take place.
Clashes between rival militias are common, with fighting at Tripoli’s airport last week leaving 20 dead and forcing the cancellation of all flights for five days.