Libya's pro-government forces on Monday cornered Islamic State group militants in their last holdouts in the coastal city of Sirte, after heavy fighting that left dozens of dead and wounded.
The battle for IS group's North African stronghold was launched more than three months ago by forces loyal to the Tripoli-based Government of National Accord (GNA).
Loyalist forces have been backed by US air raids for almost a month, amid international concern over the militants' growing influence.
IS group overran the Mediterranean hometown of Libya's slain dictator Moamer Kadhafi in mid-2015, sparking fears the militants would use it as a springboard for attacks on Europe.
Pro-GNA forces on Monday said they had encircled the jihadists in less than two square kilometres (0.7 square mile) of Sirte, after staging an assault the previous day on its last two IS-held districts.
The anti-group fighters "seized a little more than half of district Number Three and 70 percent of district Number One" in the city's downtown seafront area, they said.
At least 34 pro-GNA fighters have been killed and 185 wounded since they began their "final battle" to retake the whole of Sirte on Sunday, the hospital for the loyalist forces said.
IS group casualty figures have been unavailable.
The militants had deployed at least 12 suicide car bombs in a last bid to slow the loyalist advance, pro-GNA forces said.
After sporadic clashes during the night, the front was calm on Monday morning, according to an AFP photographer in the city 450 kilometres (280 miles) east of Tripoli.
"Our forces are preparing to launch a new assault on the area where Daesh is encircled," said a spokesman for the pro-GNA campaign, Reda Issa, using an Arabic acronym for IS.
In June 2015, IS group fighters seized Sirte, hoisting their black flag above the city's buildings.
Pro-GNA forces fought their way into Sirte a year later, this June 9, but their advance has been hampered by snipers, suicide bombings and booby traps.
More than 370 loyalist fighters have been killed and nearly 2,000 wounded in the battle for Sirte since May, according to medical sources.
The pro-GNA forces are mostly militias from western cities backing the unity government of premier-designate Fayez al-Sarraj and the guards of oil installations that IS has repeatedly tried to seize.
Backed by US air strikes since August 1, they managed to seize the militants' headquarters at the Ouagadougou conference centre on August 10, pinning down IS fighters near the sea.
As of August 24, US warplanes had carried out 82 strikes, according to the US Africa Command.
Since Tuesday, the United States has also begun using more precise AH-1W SuperCobra attack helicopters in the operation.
The United States also leads a coalition fighting IS group in Syria and Iraq, where the militants seized large swathes of territory in 2014.
Analysts say ousting IS group from Libya would be a symbolic boost for the country's fragile unity government, but unrest might continue as IS group could carry out more scattered attacks across Libya.
Before it was seized by IS group, Sirte was home to some 120,000 residents, but a pro-GNA military leader said this month that all had fled except for the families of the militants.
Pentagon spokesman Gordon Trowbridge this month estimated that militants in Sirte numbered fewer than 1,000.
IS group took advantage of the chaos in Libya after the 2011 uprising that toppled and killed Kadhafi, as rival militias and authorities have vied for control of the oil-rich country.
A UN-brokered deal struck in December led to Sarraj's unity government starting to work in the capital Tripoli, but it has since struggled to fully assert its authority over the country.
The presidential council headed by Sarraj said last Wednesday it would present a new cabinet line-up in an attempt to secure the backing of parliament.
The legislature rejected a previous line-up on August 22, setting a "final" time limit of 10 days for the council to propose a new cabinet team.