US-backed fighters said Friday they were preparing for a final assault on the Islamic State group's Syrian bastion Raqa, likely next month, with new weapons and armoured vehicles promised by Washington.

US-backed fighters cornered the Islamic State group in a last part of Tabqa on Monday, after tearing down a huge jihadist flag that had fluttered over the northern Syrian city.

A US-backed Kurdish-Arab alliance is advancing against the Islamic State group in the key town of Tabqa near the jihadist bastion of Raqa in northern Syria, a monitor said on Sunday.

A US-backed alliance of Arab-Kurdish forces entered the key jihadist-held town of Tabqa on Monday as they pursued their campaign against the Islamic State group in northern Syria.

US-backed fighters have advanced to the edge of a key jihadist-held town in northern Syria, a monitor said Saturday.

Fighters from the Syrian Democratic Forces, a US-backed Kurdish-Arab alliance, Sunday entered an military airport held by the Islamic State jihadist group in northern Syria, a spokesman said.