BENGHAZI, Libya — At least five Libyan troops were killed late on Friday when a mortar landed in the eastern city of Benghazi where pro-government forces have been fighting against a mix of Islamist militant brigades, medical sources said. Benghazi is just one front in a complex conflict involving Libya's two rival governments, and loose alliances of armed factions as well as militant forces taking advantage of the chaos to gain ground. “Five members of the Libyan National Army were killed when a mortar shell landed among them late Friday evening,” the medical source at Benghazi's Al-Jala hospital told Reuters. The source said at least 20 troops had been killed in fighting in June. LNA Mohamed Hejazi said their forces had been fighting in around six districts in the city. “These militant groups have become individuals who are taking high building as posts. The militants have also booby-trapped all houses and streets,” Hejazi said. Army forces loyal to Libya's internationally recognized government have been fighting several Islamist groups in Libya's second-largest city as part of a wider struggle since the overthrow of Muammar Gaddafi in 2011. Fighters claiming allegiance to the Islamist State group holding parts of Iraq and Syria have also claimed attacks in Benghazi as that group looks to expand its foothold in Libya. Pro-government forces in Benghazi have regained some territory lost last year. But progress has stalled as militants hole up in several districts and the port area despite claims by army commander Khalifa Haftar that his forces control most of the city. Libya's recognized government operates out of the east since an armed faction known as Libya Dawn took over the capital Tripoli last summer and declared its own government. Ongoing United Nations negotiations to end the conflict and bring the two main factions into a unity government and broker a broad ceasefire have struggled as both sides seek more concessions over their rivals. — Reuters