Defeat in Sirte will damage ISIS’s ability to show it is expanding globally and deprive it of a foothold outside Iraq and Syria.

After six months of heavy fighting, Libyan forces have advanced so deep into the strategic city of Sirte that they can pick out the Tunisian and Egyptian accents of their ISIS enemies as they trade insults over the frontline.

Victory is imminent on this remote front of the war against ISIS, with the last few militants staging a last stand in a small area of just one square kilometer (0.4 square mile), US and Libyan officials say.

But the battle has been long and hard, and holds lessons for US backed forces trying to force ISIS out of the much larger Iraqi city of Mosul more than 2,500 km (1,500 miles) away.

‘We faced unbelievable resistance. They won’t leave their posts even when houses are collapsing on them,’ said Osama Issa, a 37-year-old businessman fighting with Libyan forces in Ghiza, the last neighborhood of Sirte that ISIS holds.

‘They know they will die anyway so they fight well.’

Defeat in Sirte will damage ISIS’s ability to show it is expanding globally and deprive it of a foothold outside Iraq and Syria. Losing it and Mosul in quick succession would dent its morale and possibly its ability to recruit followers.

But the militants in Sirte have inflicted heavy losses on the Libyan fighters — at least 660 have been killed and 3,000 wounded — and held out longer than expected.

They have proved their skills in guerrilla warfare, shown the vulnerability of advancing forces that lack expertise in urban warfare and highlighted the limited effectiveness of air strikes when frontlines are so close.

The battle has also underlined the importance of trapping fighters during battle because many have escaped from Sirte — a Libyan commander put the number at 400 — and are now staging attacks behind frontlines with increasingly sophisticated bombs.

Growing rivalry between the various factions in the Libyan forces also serves as a warning to the diverse groups fighting ISIS in Mosul: the end of the battle may bring political chaos and the risk of new military conflicts.

[vuukle]