Beirut: US-backed Syrian fighters advancing on the Islamic State group in the strategic northern town of Manbij have progressed to within five kilometres of the jihadist bastion, a monitor said on Sunday.
Supported by air strikes by the US-led coalition battling IS in Syria and Iraq, the Syrian Democratic Forces (SDF) alliance of Kurdish and Arab militias launched an assault last week on Manbij.
"The Syrian Democratic Forces are now within about five kilometres of the strategic city of Manbij," said the Syrian Observatory for Human Rights, a Britain-based monitoring group.
Manbij is located along a route connecting Raqa - the IS group's de facto capital in Syria -- to the Turkish border, a vital conduit for supplies and foreign fighters.
At least 74 people have died in the fighting since the start of the offensive last Monday, including 32 civilians mainly killed as a result of coalition air strikes, said the Observatory, which relies on a network of medics and activists to monitor the conflict.
Thirty jihadists were also killed, it said, along with 12 SDF fighters.
After taking the village of Khirbet al-Rus, about 20 kilometres southeast of Manbij, the SDF rescued a group of Yazidis -- six women and 16 children -- who were being held captive by IS, the Observatory said.
The women and children were among hundreds of Yazidis taken captive in mid-2014 as IS carried out a brutal campaign of massacres, enslavement and rape against members of the Yazidi minority.
US Central Command spokesman Colonel Patrick Ryder said yesterday that SDF fighters had seized more than 100 square kilometres of territory during the advance.
More than 55 air strikes have been carried out since the offensive began, he said, adding that the goal was to hamper IS's ability "to move fighters, weapons, finances (and) supplies into and out of Syria and Iraq."
Some 3,000 Arab fighters were taking part in the offensive, backed by around 500 Kurdish militia members, he said, adding that US special forces were working "at the command and control level" in the operation.
Russian-backed Syrian troops are also advancing against IS in Raqa and yesterday pushed into the province from the southwest, moving to within 40 kilometres of the Euphrates Valley town of Tabqa, site of the country's biggest dam.