Syrian Kurdish fighters have expelled fighters of al-Qaeda-linked groups from a checkpoint in the northeast of the country and seized their weapons and ammunition, according to the Syrian Observatory for Human Rights.
"Clashes raged during the night from Friday to Saturday, pitting [Kurdish fighters] against Al-Nusra Front, ISIS and other [rebel] groups... near the villages of Tal Alu, Karhuk and Ali Agha," said the Britain-based Observatory on Saturday.
The Kurdish fighters then seized ammunition, light weapons, a vehicle mounting a heavy machine gun and a mortar launcher from the fighters, the monitoring group added.
The advance comes just days after Kurdish fighters loyal to the Democratic Union Party (PYD) expelled fighters allied to the Al-Nusra Front and the Islamic State of Iraq and the Levant (ISIS) from the strategic Kurdish town of Ras al-Ain.
The PYD chief Salih Muslim has stated that Syria's Kurds are planning to create a temporary autonomous government to administer their regions in the north.
Kurdish regions have been administered by local Kurdish councils since President Bashar al-Assad's forces withdrew from the areas in mid-2012.
The redeployment was seen as a tactical move by the regime, freeing up forces to battle rebels elsewhere, and encouraging the Kurds to avoid allying with the opposition in order to maintain their new-found autonomy.
Meanwhile in northwestern Syria, the air force kept up a fierce campaign against the town of Saraqeb and staged 10 air strikes there on Saturday, killing three children, the Observatory reported.
The strikes on the rebel-held town in Idlib province also killed a medical volunteer and a woman, the group added.
Air raids also hit areas where the rebels were reportedly advancing in Aleppo province in northern Syria, it said.
The raids came as rebels advanced on Khan al-Assal, the only town in the west of Aleppo province still under regime control.
Saturday's violence comes a day after at least 95 people were killed across Syria, said the Observatory.
More than 100,000 people, most of them civilians, have died in Syria's 28-month war, the group says.