The killing of one of the most senior Al-Qaeda-linked figures in the Libyan city of Derna has sparked clashes between a militia with strong ties to the group and Islamic State fighters.
Nasser Aker, a senior figure in Derna's Jihadi Shura Council was shot and killed by masked gunmen along with a second man accompanying him, named in unconfirmed reports as Faraj Al-Houthi, on 9 June.
Aker, a seasoned militant, lived in Sudan in the 1990s at the same time as Osama Bin Laden and later fought in Afghanistan. Associated Press has reported that he was also jailed in the UK on terrorism charges.
A spokesman for Libya's Islamist-leaning, Tripoli government, Jamal Zubia, said security sources had confirmed the killings and said it was believed ISIS was responsible. He added that Aker's death had led to clashes in Derna between Islamic State and another radical group, Abu Saleem Martyr's Brigade.
At least nine IS fighters have been killed in the ensuing battle and two from Abu Saleem Martyr's Brigade, including Salem Derbi, its commander, AP reported. The Abu Saleem brigade has vowed to wipe out IS in Derna, in response to the attack on Aker.
The brigade had held the balance of power in Derna until last year when a smaller offshoot known as the Council of Islamic Youth declared its allegiance to Islamic State and started drawing fighters to its cause.
Since then a tentative truce between the two groups has frequently fallen apart, resulting in violence.
Some of the worst atrocities in Libya have been carried out by Islamic State in Derna. IS beheaded a postal worker last week it claimed had volunteered to fight with the Libyan National Army.
The jihadi group has increasingly targeted migrants working in Libya or those travelling through the country to board boats to Europe. In February, IS executed 21 Egyptian Coptic Christians on a Libyan beach. In April, the group beheaded 30 Ethiopian migrants and published propaganda showing the murders online.
IS has exploited a political vacuum in Libya over the past year, using a stalemate between the country's two rival governments to exert its control. A number of Islamist militias, remnants of Libya's 2011 liberation war, have allied themselves with the group.
A second offshoot of Islamic State in Libya, based predominantly in the central city of Sirte, has claimed complete control of the town, saying it yesterday overran the main power station.