Kurdish forces on Monday seized almost full control of the Syrian border of Tal Abyad from the Islamic State group after forcing most of the jihadists to flee, a monitor said.

"The Kurdish fighters are in almost full control of Tal Abyad," said the director of the Britain-based Syrian Observatory of Human Rights about the town which IS held to preserve a key supply line.

Abdel Rahman said there were still "some small pockets of resistance from small groups of Islamic State fighters who are still holed up inside".