Dozens of displaced people with Islamic state fighters among them evacuated from Baghouz - the last town still under the control of Islamic State group.
Hundreds of civilians streamed out of the Islamic State group's last Syrian stronghold Tuesday into territory held by US-backed forces battling to finish off the jihadists' dying "caliphate".
The new exodus came only three days after the Kurdish-led Syrian Democratic Forces resumed military operations against the militants holed up in Baghouz, a village on the banks of the Euphrates River close to the Iraqi border.
The U.S. -backed forces slowed their push on Baghouz last week to allow civilians to leave the tiny enclave.
"I would characterize the number of IS fighters now in SDF custody as thousands", Navy Commander Sean Robertson, a Pentagon spokesman, said in a statement, referring to the IS.
Most of the remaining militants in the Baghouz area are reportedly foreign recruits, intent on fighting to the end, ignoring the SDF's ultimatum to either lay down their weapons or face a final ground offensive.
Fabien Clain was killed in a strike by the USA -led military coalition in Syria in February. They left through a humanitarian corridor established by the Kurdish-led forces for those who want to leave or surrender.More news: Trump today: Paul Manafort jailed
The SDF said its fighters were surprised by the number of civilians, who include IS family members, cooped up in the small area that has been squeezed smaller and smaller by intermittent military offensives.
Among those who arrived at the camp in Al-Hol, 10 people "needed urgent medical treatment because of shrapnel or war injuries", the International Relief Committee said.
Around 15,000 people have reached the Al-Hol camp from Baghouz between February 22 and March 1, the UN's humanitarian coordination office OCHA said on Monday.
Robert Mardini of the International Committee for the Red Cross said in NY on Monday that the population in the camp has risen from 34,000 at the beginning of December to 45,000 now.
The government has declared that Hoda Muthana, 24, is not an American citizen, and has barred her from entry.
"Everything happens outdoors, there are no houses anymore, everybody lives outside, which is not surprising because we were being bombarded day and night", she said.
While the capture of Baghouz would mark a milestone in the fight against IS, the group is expected to remain a security threat as an insurgent force with sleeper cells and some pockets of remote territory.