Syrian Kurdish fighters advanced towards the Islamic State (ISIS) group-held town of Tal Abyad on the Turkish border on Thursday, backed by US-led coalition strikes, a monitor said.
The Syrian Observatory for Human Rights said Kurdish People's Protection Units (YPG) forces backed by Arab rebel fighters "stormed the town of Suluk and took control of the eastern part of it," reports AFP.
Fierce clashes continued through the day between ISIS and Kurdish forces.
Suluk, in the ISIS bastion province of Raqa in northern Syria, lies to the east of Tal Abyad, a key border town that is controlled by the jihadist group.
The town is a key target for the Kurds who want to free up the route between Kobane to the west and Qamishli, further east along the Turkish border.
With their advance into Suluk, YPG forces are now some 20 kilometres (12 miles) east of Tal Abyad, and they are also positioned around 10 kilometers to the west.
"The Kurds plan to lay siege to Tal Abyad," Observatory director Rami Abdel Rahman said.
The YPG has been backed by US-led air strikes targeting ISIS positions in the area, he added.
The latest fighting in the area has prompted a wave of several thousand people to flee into neighboring Turkey, which is already hosting 1.8 million Syrians.
Nearly 9,000 refugees have entered Turkey since last week, a Turkish official said on Wednesday.