"As ISIL attempts to run, they are continuing their tactic of intermixing with innocent civilians and using them as human shields," Rankine-Galloway stated.
The spokesperson noted that the campaign to liberate Manbij from the terrorists has entered its final stages, with a few remaining pockets of fighting in the north.
Earlier on Friday, local media reported that Daesh took some 2,000 Manbij residents as hostages while fleeing the city.
"While we cannot comment on a specific number, it should come as no surprise that ISIL would result to the cowardly actions of kidnapping and using human shields as they attempt to flee Manbij," Rankine-Galloway said.
On May 21, Syrian Democratic Forces, backed by the US-led coalition, began an offensive to retake the Syrian city of Manbij from Daesh, which is banned in many countries.
"We assess many of the ISIL terrorists killed there have been foreign fighters often used to conduct external terror attacks," Rankine-Galloway also stated.