[33] On 19 May, an ISIL suicide bomber attacked GNA forces, 90 kilometers west of Sirte, killing 30 soldiers and wounding 50.

[40] On 4 June, GNA forces captured the Ghardabiya Air Base, 10–20 kilometers south of Sirte's center.

[49] In addition, the Libyan Navy secured Sirte's coast and blocked potential escape routes for ISIL via the sea.

[12] The following day, street fighting continued to rage in Sirte and heavy clashes took place around the Ouagadougou complex, with GNA forces hitting with artillery fire ISIL positions around the conference centre.

[50] On 12 June, GNA forces secured both Sirte's port, airport[32] and a residential area in the east of the city, while fighting was continuing two kilometers from the conference hall.

[51] ISIL fighters in the city retreated into a densely built-up area, with snipers taking up positions against the advancing GNA forces.

[53] Three ISIL suicide car-bombers targeted a field hospital in the west of Sirte, as well as two positions of GNA fighters, including at the Abu Hadi roundabout in the southeast of the city.

[55] On 16 June, a suicide attack at a police station in Abu Grain, at a crossroad between Sirte and Misrata, killed 10 soldiers and wounded 7.

During the fighting, three ISIL suicide car-bombers, including a Libyan and an Egyptian, hit GNA forces in an unsuccessful counter-attack.

[70] On 1 August 2016, the Pentagon announced the U.S. military effort to support the Libyan government against ISIL would be code-named Operation Odyssey Lightning.

[71] On 1 August, at the request of the GNA, the United States Navy and United States Marine Corps Harriers and helicopters launched from USS Wasp (LHD-1) and USS San Antonio, began to bomb Sirte, targeting ISIL tanks and vehicles in support of the GNA forces.

[73] During these airstrikes, another Sudanese ISIL commander, Qusai al-Jaili, was reportedly killed, though other sources said he had died of illness or wounds.

Al-Jaili had achieved prominence by masterminding the escape of four assassins of U.S. diplomat John Granville from Kober Prison in Khartoum in 2009.

[76] Two days later, GNA forces took control of the Ouagadougou centre, Sirte's Ibn Sina hospital and the university campus.

In one room, there were boxes of gold, jewelry, wads of Tunisian currency, rifles and shotguns, computers, radios and cartons of telephone cards.

[99] On 3 September, pro-GNA militias launched an offensive on the last-ISIL held areas of Sirte and stated they had captured several buildings including two banks and a hotel.

[100][101][102] On 5 September, the media wing of Al-Bunyan Al-Marsous reported that it had captured ISIL pockets in the Jizah neighbourhood including a Wihda Bank branch.

[103] On 6 September, the pro-GNA forces captured the buildings of the civil court and the savings bank in neighbourhood 3 in addition to an ammunition stockpile belonging to the militants containing mines, explosives and warheads.

Pro-GNA militias stated they had captured the Social Security headquarters, an ISIL field hospital, Fateh School, Grand Mosque and a workshop for manufacturing explosives.

Three car bombs were destroyed before reaching their targets, while the spokesman for Misratan militias stated that the militants had been cut off from each other and surrounded in two different areas.

[117] The same day, an attack by ISIL militants on a GNA checkpoint from outside Sirte, near Ghardabiya Air Base, in a possible attempt to lift the siege of the city, was repelled.

[121] On 7 October 2016, GNA forces managed to separate the last ISIL-controlled areas in Sirte, after taking control of the dividing line between the "600" neighbourhood and the sea-view Jizah apartment buildings.

[134] On 26 October, GNA militias launched an attack on the Jizah neighbourhood by shelling it with heavy artillery,[135] managing to take control of several residential blocks by the following day.

They also stated that they were taking a step-by-step approach to limit casualties among their ranks, as well as the civilians held as human shields by ISIL.

[164] The GNA captured nine buildings on 4 December, with 10 women and children leaving ISIL-held area,[165] while 2 militants, who tried to escape, were arrested.

[167] By 6 December, ISIL was in control of less than 10 houses, with the GNA trying to neutralize a small number of militants still present in the area and rescuing a group of women and children.

[177] Another spokesman Ahmes Hadiya stated that while it was the last major battle, it wasn't the end of military operations or a declaration of liberation.

[178] The Military Intelligence Chief, Ismaeil Al-Shukri later in a televised statement denied that diehard militants had escaped the city.

[184] GNA's Prime Minister Fayez al-Sarraj officially announced the end of military operations and "liberation of Sirte" on 18 December.

UN's envoy to Libya Martin Kobler termed the ISIL defeat as a major step towards ending terrorism in the country and called for national reconciliation.