A US-backed alliance of Syrian forces announced on Tuesday it would redeploy around 1,700 fighters from front lines against the Islamic State group to a Kurdish enclave under Turkish attack.

"We took the difficult decision to pull our forces out of Deir Ezzor province and battlefronts against Daesh (IS) to head to the Afrin battle," said Abu Omar al-Idlibi, a commander of the Syrian Democratic Forces.