The battle to capture the extremist group's last speck of territory in eastern Syria began in September and has dragged on amid an exodus of civilians from the area.
A final push by Kurdish-led Syrian Democratic Forces started on January 9, but has been paused on several occasions, mainly to allow for civilians to evacuate and fighters to surrender.
The SDF have been repeatedly surprised to discover just how many civilians were holed up in the area - a collection of tents covering foxholes and underground caves in the village of Baghouz - alongside the IS fighters. In the last two weeks, many fighters appeared to be among those evacuating.
On Sunday, dozens of men and women were seen walking around the besieged IS encampment in Baghouz, as SDF fighters watched from a hilltop close by.
The camp, looking much like a junkyard, was littered with damaged vans and pickup trucks parked between tents where people appeared to be moving about.
On the hilltop lookout north of Baghouz, an SDF sentry, lying flat on his stomach with his rocket launcher trained on the camp, cautioned an approaching comrade not to get too close. "There are snipers," he said of the IS camp.
SDF spokesman Kino Gabriel said the camp was approximately 0.25 square kilometers in size - much the same area it was five weeks ago, when the SDF said it was finally going to conclude the battle.
"We are facing several difficulties regarding the operations," Gabriel told reporters outside Baghouz on Sunday.
He cited the large number of mines and explosive devices planted by IS and the existence of tunnels and hideouts beneath the ground that are being used by the militants to attack SDF forces or defend themselves.
An earlier look at the camp showed tents pitched over trenches and foxholes, suggesting the possibly of a substantial tunnel network that the SDF says is hindering its advance.
In the middle of the camp stands a pair of two-floor compounds, showing little sign of damage. Several houses that appeared habitable can be seen as well.
Gabriel said 29,600 people have left Baghouz since Jan. 9, among them 5,000 fighters - far greater than the SDF had initially estimated remained inside.
He said the SDF would no longer estimate how many people remained in Baghouz but said recent evacuees told the fighting forces that another 5,000 were still inside.
The SDF and the Kurdish-led authorities that administer northeast Syria have banned in recent days journalists from interviewing evacuees from Baghouz.
The evacuees are now living in detention-like camps in the self-administered region that international humanitarian organizations say are vastly overcrowded and underserved. They say disease is rampant in the camps and medical care is desperately needed.
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