US-backed Syrian forces say they are close to capturing a Daesh-held town that lies halfway between the former Daesh-stronghold of Tabqa and its de facto capital, Raqqa, in northern Syria. The Kurdish-led Syrian Democratic Forces say they are in control of 90 percent of the town of Mansoura, approximately 26 kilometers (16 miles) southwest of Raqqa. The Britain-based Syrian Observatory for Human Rights says the SDF has been engaged in fierce fighting with Daesh (the so-called IS) militants along the southern bank of the Euphrates River, around Mansoura. The river leads to Raqqa. The US has backed the SDF with weapons, airpower, and ground support in its campaign to defeat the Daesh group in Syria. Its target for now is Raqqa, which has been held by the militants since 2014. Meanwhile, the Syrian army said on Saturday it had seized mountainous territory from Daesh to the east of the road linking Damascus to Aleppo, helping to secure a critical lifeline for the government that has often come under IS attack. The army also said it had seized 22 villages and farms from IS near Maskaneh, the last major IS-held town in Aleppo province. The capture of Maskaneh will bring Russian-backed government forces to the border of Raqqa province, much of which is held by US-backed groups that are also fighting IS. The army said it had captured the northeastern and central portions of a mountain range to the east of the Khanaser-Ithriya road. "It certainly widens the circle of security around the Damascus-Aleppo road," a military source told Reuters. The Khanaser-Ithriya road is the only government-controlled route linking Aleppo to other government-held cities of western Syria. Sections of the main highway to Aleppo, which runs through western Syria, remain in rebel hands. The town of Maskaneh is located on the western banks of the River Euphrates in Aleppo province some 10 km from the provincial border with Raqqa. The next major urban center to the east is Tabqa, which was captured from IS by the US-backed Syrian Democratic Forces (SDF) in May. In a related development, RIA news agency quoted the Syrian ambassador to Moscow as saying on Saturday that the next round Syria peace talks will be held in the Kazakh capital of Astana on June 12-13. "We have received an invitation to participate in talks in Astana, which will take place on 12-13 of this month," RIA quoted Ambassador Riad Haddad as saying. — Agencies