Heavy clashes as US-backed forces battle IS in Syria

French General Jean-Marc Vigilant (L) and French Defence Minister Florence Parly (2nd L) talk to French soldiers engaged in the "Operation Chammal", the French military operation within "Operation Inherent Resolve", the international coalition against the Islamic State (IS) group, as they stand in front of a wheeled 155 mm gun-howitzer CAESAR system (truck equipped with an artillery system) on February 9, 2019, near Al-Qaim, a few kilometres away from the last scrap of territory held by IS in eastern Syria. The US-backed Syrian Democratic Forces said on February 9, 2019 it had begun the "final battle" to oust the Islamic State group from the last scrap of territory it holds in eastern Syria. AFP photo

US-backed forces were locked in fierce fighting as they pressed the battle against the last shred of the Islamic State group's "caliphate" in eastern Syria on Sunday, a war monitor said.

The Syrian Democratic Forces (SDF), supported by a US-led coalition, announced a final push to retake the jihadist pocket near the Iraqi border late Saturday, after a pause of more than a week to allow civilians to flee.

The Syrian Observatory for Human Rights reported heavy clashes between both sides on Sunday morning, as coalition planes and artillery bombarded jihadist positions.

"The battle is ongoing. There were heavy clashes this morning, with landmines going off," said Rami Abdel Rahman, the head of the Britain-based war monitor.

The SDF launched an offensive to expel IS from the eastern province of Deir Ezzor in September.

The Kurdish-led alliance has since whittled down jihadist-held territory to a patch of just four square kilometres (one square mile) on the eastern banks of the Euphrates.

Up to 600 jihadists could still remain inside, most of them foreigners, according to SDF spokesman Mustafa Bali.

Since fighting intensified in December, more than 37,000 people, mostly wives and children of jihadist fighters, have fled out into SDF-held desert areas, the Observatory says.

That figure includes some 3,200 suspected jihadists detained by the SDF, according to the monitor, which relies on sources inside Syria for its information.

At the height of their rule, the jihadists imposed their brutal interpretation of Islamic law on a territory spanning parts of Syria and Iraq that was roughly the size of Britain.

But separate military offensives in both countries, including by the SDF, have since retaken the vast bulk of the cross-border "caliphate" they declared in 2014.