US-backed, Kurdish-led fighters have captured the last town held by the Islamic State group after days of intense battles in the militants’ remaining enclave in eastern Syria, activists said.

The fall of Hajin is a blow to the extremists. The town was their main stronghold in the last pocket of land they control in eastern Syria, near the Iraqi border. IS still holds some villages nearby.

The Kurdish-led Syrian Democratic Forces have been fighting to take Hajin and surrounding villages in Deir el-Zour province for more than three months. In recent weeks, the offensive intensified with the arrival of reinforcements from northern Syria.

The Britain-based Syrian Observatory for Human Rights said the SDF took Hajin early in the morning after fierce fighting under the cover of air strikes by the US-led coalition.

It said some IS fighters withdrew to the villages and fighting is still going in the fields outside Hajin as SDF troops chase the extremists.

Europe-based activist Omar Abu Layla of the DeirEzzor 24 monitoring group confirmed the town was taken, adding that some IS fighters are still holed up in small pockets on the edge of Hajin.

He said that in IS ranks, disagreements over hierarchy helped “speed up the collapse” of defences in Hajin.

Nuri Mehmud, spokesman of the Syrian Kurdish militia known as the People’s Protection Units, or YPG — the main component of SDF — said “intense fighting” is continuing in small parts of Hajin.

The area was home to 15,000 people, including 2,000 IS gunmen who fought back with counter-offensives and suicide attacks.

Over recent days, hundreds of civilians fled the enclave towards areas controlled by the SDF east of the Euphrates River and government-controlled regions on the river’s west bank.

The Syrian Democratic Council, the political wing of the SDF, denounced Turkey’s threat of a military operation against the YPG and called on Syrians of all ethnic and religious groups to unite ahead of a possible Turkish attack.

Meanwhile, Turkish President Recep Tayyip Erdogan intensified his criticism of US support for the Syrian Kurdish fighters, saying Turkey would clear the key northern town of Manbij.

Over the summer, the two Nato allies had struck a “road map” for Manbij to remove the YPG, which Turkey considers a terror organisation linked to an insurgency within its own borders.