At least 17 people were killed in heavy clashes between Islamic State fighters and a rival Islamist group in the Islamic State-held city of Sirte in central Libya on Thursday, residents said.
Earlier this week, a Salafist Muslim group and armed residents attacked Islamic State fighters in Sirte, located about 500 km east of the capital Tripoli, accusing them of killing a prominent preacher in Sirte.
Around 15 local fighters and two Islamic State commanders were killed, residents said. The battle was concentrated in one district where locals had surrounded Islamic State fighters holed up in buildings, they said.
Reuters has unable to verify the information from the city, which was seized by Islamic State seized Sirte earlier this year.
A similar battle occurred in the eastern city of Derna in June when Islamic State was expelled by rival Islamist fighters who teamed up with locals angered by the arrival of foreign militants and clerics.
Islamic State launched an offensive to retake Derna this week.
Libya has two governments fighting each other for power while Islamic State and other armed groups exploit a security vacuum to carve out their own fiefdoms.
Both governments are also battling militants in different parts of Libya.
The United Nations brought the main warring factions together in Geneva this week but the diplomacy has been overtaken by fighting between groups not present at the negotiation table.