BEIRUT — US-backed Syrian fighters including Kurds advanced against Daesh (the so-called IS) in the last tract of territory the group holds near the Turkish border on Wednesday, a monitoring group said, opening a major new front with US-led air support. US officials separately told Reuters that thousands of fighters, supported by a small number of US special forces, were launching an offensive to capture the crucial swathe of northern Syria that militants have long used as a logistics base. The operation could take weeks. The Syrian Observatory for Human Rights said the Kurdish YPG militia made up the majority of the fighters taking part in the assault by the Syria Democratic Forces (SDF) alliance, with the initial target of capturing the town of Manbij, contradicting US officials who said the bulk were Arabs. This is seen as important to NATO member Turkey, which has opposed any further expansion of Syrian Kurdish sway at the frontier. The Syrian Kurdish YPG militia already controls an uninterrupted 400 km stretch of the border. A US official said Turkey supported the offensive. SDF and YPG officials could not immediately be reached for comment. The Observatory said US-led airstrikes in support of the ground operation killed 15 civilians including three children near Manbij in the last 24 hours. The observatory's reporting is based on an activist network in Syria. It said the SDF fighters had taken 16 villages and were at a distance of 15 km from Manbij. Driving Daesh from its last remaining foothold at the Turkish border has been a top priority of the US-led campaign against the group. The group controls around 80 km of the frontier stretching west from Jarablus. Syrian rebel groups deemed moderate by the West have been waging a separate campaign against Daesh in the same corridor, but further west near Azaz. The going has proved tough, with Daesh repeatedly counter attacking. Turkish border The US officials said the operation got underway on Tuesday and aims to choke off Daesh's access to territory that militants have long used to move foreign fighters back and forth to Europe. "It's significant in that it's their last remaining funnel" to Europe, a US military official said. The US officials said Kurdish YPG fighters would only represent a fifth or a sixth of the overall force. Turkey considers the YPG a terrorist group due to its links with the Kurdistan Workers Party (PKK), which is waging an armed insurrection in southeastern Turkey. The US officials said the YPG will only fight to help clear Daesh from the area around Manbij. Syrian Arab fighters would be the ones to stabilize and secure it once Islamic State is gone, according to the operational plans. "After they take Manbij, the agreement is the YPG will not be staying ... So you'll have Syrian Arabs occupying traditional Syrian Arab land," the official said. But observatory Director Rami Abdulrahman said: "The majority are from (YPG), and the operation is basically a YPG operation." Syrian Kurdish groups have established their own government in northeastern Syria since 2011. Capturing the last remaining Daesh foothold at the Turkish border would help them to link up with the area of Afrin, which is controlled by the same Kurdish groups in northwestern Syria. The YPG has been the most effective ally on the ground for US-led airstrikes against Daesh, and last year captured large areas from it in Hasaka province. The SDF alliance, including some Arab militias, was formed in October, since when it has led the campaign against Daesh with US support. The SDF last week began attacks against Daesh in areas north of its de facto capital of Raqqa, but says the city was not a target of that operation. — Reuters
