Fire and bombs amid the palm groves: This is what the final battle against Isis looks like

Children exit the back of a truck as they arrive to a US-backed Syrian Democratic Forces screening area after being evacuated out of the last territory held by Islamic State militants. Photo / AP

Hundreds of fighters and civilians trudged out of the Islamic State's final scrap of territory in eastern Syria this weekend after US-led forces pummeled it from the ground and sky. Once the size of Britain, the self-declared Islamic caliphate is just a warren of tents and tunnels now. But the final battle has been grindingly slow.

On Monday the US-backed Syrian Democratic Forces, or SDF, said that its forces were advancing slowly on account of the number of civilians still trapped inside the village of Baghouz. Thousands have left the village in recent weeks, but an unknown number remain. Some are too scared to leave, escapees say. Others are refusing to abandon the cause, even in its dying days.

Columns of black smoke rise from the last small piece of territory held by Islamic State militants as US backed fighters pound the area with artillery fire and occasional airstrikes. Photo / AP

After a 10-day truce to encourage more surrenders, the battle resumed this weekend with a ferocity previously unseen in the small corner of Syria. The earth and palm trees shook as bombs rained down. At night, fires framed the silhouettes of what remains of Baghouz. Victory, the SDF predicted, will come "in a short period."

A US-backed Syrian Democratic Forces fighter waits to be taken to an advanced position near the last land still held by Islamic State militants in Baghouz. Photo / AP

But once the guns fall quiet and the battle is over, the challenge ahead will in many ways be more complicated. The Islamic State has already adapted to its loss of territory, melting back to its insurgent roots in Iraq and seeding sleeper cells across eastern Syria, too. In this part of Syria, the prospects for stability are dependent on a range of factors, including how the US military withdrawal shakes out and whether the SDF then cuts a deal with Syrian President Bashar al-Assad's government in return for some sort of protection.

A girl waits to be screened by US-backed Syrian Democratic Forces after being evacuated out of the last territory held by Islamic State militants, in the desert outside Baghouz, Syria. Photo / AP

When the dust settles in Baghouz, other questions might be answered. The fate of hundreds of prisoners - among them Western hostages - remains unknown. There is also the question of the Islamic State's missing leadership. Western militaries suspect that the group's so-called caliph, Abu Bakr al-Baghdadi, has slipped into Iraq. He has delivered no message to his die-hard cadres in the final stage of their battle.