Around 400 Islamic State jihadists fled the group’s last occupied area in Syria on Wednesday as US-backed forces continued to besiege the stronghold.
The IS fighters were captured trying to escape Baghouz with smugglers, a senior Syrian Democratic Forces (SDF) commander said.
Hundreds of other militants surrendered, though the exact amount is unclear.
The groups were among more than 2,000 people who left Baghouz in the latest evacuation. They were transported by trucks to a patch of desert.
There they were given food and water while also being questioned and searched.
The SDF said about 6,500 people had left the area over the previous two days, including hundreds of men.
Children who had been captured by the jihadists were also among those released, including 11 from the Yazidi community and four Shi'ite Muslim children abducted from the Iraqi city of Tel Afar four years ago.
An SDF spokesman said they will try to reunite them with their parents.
There was a heavy assault on the IS enclave on Saturday and Sunday which prompted the surrenders, though it is unclear how many more people remain inside.
The fall of Baghouz would mark the end of the rule of Islamic State's self-proclaimed "caliphate" over populated territory,
However, some fighters are still hiding out in remote desert or have gone underground to wage a guerrilla insurgency.
The Syrian Observatory for Human Rights said there were preparations in eastern Syria to announce the end of Islamic State there.
Colonel Sean Ryan, spokesman for the US-led coalition backing the SDF, said the international force had "learned not to put any timetables on the last battle".
The offensive on Baghouz resumed last Friday after a two-week break to allow for the evacuation of civilians.
Retaking the land in Syria would be a milestone in the devastating four-year campaign to end the "caliphate", which once straddled a vast territory across both Syria and Iraq.
