AL-OMAR OIL FIELD BASE, Syria -- A spokesman for U.S.-backed forces fighting the Islamic State group in Syria says they have uncovered a mass grave near the last ISIS-held pocket in the country's east.

Adnan Afrin said Thursday that the grave unearthed outside the village of Baghouz contains the remains of men and women but said the number of bodies and their identities remain unclear.

A video published by Kurdish-run Furat FM TV station emerged showing several bodies dug out from a pit.

The Kurdish-led force known as the Syrian Democratic Forces has been locked in a standoff with remaining ISIS militants holed up in Baghouz with civilians since early February.

Afrin says his forces managed to free 24 SDF fighters over the course of evacuating civilians from the area.