Sky News
US-backed forces have entered the Islamic State stronghold of Manbij in northern Syria and are slowly advancing to its centre, it has been reported.
Intense fighting is taking place between IS fighters and the Syrian Democratic Forces (SDF) on the southwestern edge of Manbij, the Syrian Observatory for Human Rights has said.
The SDF recaptured a village about 1km (0.6m) away, enabling them to seize two squares on the western side of the city, according to Rami Abdurrahman, the director of the UK-based monitoring group,
The SDF forces then advanced towards a third square with air support from the US-led coalition.
An adviser to the predominantly Kurdish SDF, Nasser Haj Mansour, said the force moved into the city from its northern edge, close to grain silos, prompting clashes with IS militants.
Earlier, the US Central Command said in a statement the SDF had consolidated their positions around Manbij in preparation for seizing it.
"For the last seven days they have been refining their plans as to how to gain a foothold in Manbij and maintain the safety of the civilian population trapped (by IS)," the statement said.
The US has embedded 300 Special Forces troops with the SDF and France is providing them with training.
Since the operation against IS in Manbij began on 31 May, the international coalition has since conducted more than 233 airstrikes in the vicinity of the city.
The IS news agency Aamaq has said its fighters had repelled an advance by the SDF from north of Manbij, adding that many retreating forces had been killed by suicide bombers.
Mr Mansour said suicide bombings would not stop the SDF advance as they were "no longer a surprise".
"The tactic and their moves have become known and ineffective, particularly when there is always air support," he said.
"They no longer have the desired impact."
The Observatory said around 63 SDF fighters had been killed since the start of the operation, compared to 458 IS militants.
Manbij is a key point on an IS supply line between the Turkish border and its de facto capital, Raqqa, which is also under intense pressure from a Syrian government offensive.
If Manbij is captured, it will be the biggest strategic defeat for IS in Syria since July 2015, when it lost the border town of Tal Abyad.