Daesh militants in Libya stormed judicial offices in the city of Sirte on Monday, declaring them "Islamic courts".

The militants stormed the headquarters of the courts and the Public Prosecution as well as the building of the national security directorate, a source of the prosecution in Sirte told Wasat news website.

The terrorist group also controlled the headquarters of Sirte Court of First Instance which is in charge of hearing marriage and divorce issues.

The group has gained a foothold in Libya by exploiting chaos and a security vacuum.

Its appearance typifies the chaos in Libya, where two rival governments and parliaments, together with an assortment of Islamists, tribesmen and armed groups, are battling for control of cities and regions, four years after the fall of veteran leader Muammar Gaddafi.