Turkish troops and Ankara-backed Syrian rebels battling the Kurdish Peoples Protection Units (YPG) in northern Syria advanced on Saturday to within just a few kilometers of the flashpoint town of Afrin, the Syrian Observatory for Human Rights said. The attacking forces "are now four kilometers away from the town of Afrin from the northeast, where there are intense clashes, air strikes, and artillery fire,” the Britain-based Observatory said. The move came a day after Turkish President Recep Tayyip Erdogan said his troops and the Syrian fighters they were backing could break into the Kurdish-controlled town "at any moment." Turkey launched operation "Olive Branch" on January 20 against the YPG, a powerful militia that controls the Afrin region in northwest Syria and which Ankara regards as a "terror group". Ankara says the YPG is the Syrian branch of the Kurdistan Workers Party (PKK). Rami Abel Rahman, head of the Observatory, said the aim was to besiege Afrin, cutting it off from other areas. But, according to him, the advance sparked "major concerns" for tens of thousands of civilians in the town of Afrin. "Olive Branch" initially made slow progress, but the capture on Thursday of Jandairis, a major town in the Kurdish-held enclave, has given the operation a clear shot at the central town of Afrin. Thousands of people have fled heavy shelling on the villages and towns near the Turkish border, many of them into Afrin town. Only one route currently leads out of the town and into regime-controlled zones in Syrias northern province of Aleppo. According to the Observatory, Turkey and allied Syrian opposition factions now hold 60 percent of the Afrin region.