Turkey and its Syrian rebel allies have stepped up attacks against Syrian Kurdish fighters in northwest Syria, part of an effort to roll back the US-supported group known as the People’s Protection Units (YPG), which Turkish officials call a threat to Turkey’s national security.

The London-based Syrian Observatory for Human Rights reported that the clashes occurred around the village of Ain Daqna and Menagh, an air base north of Aleppo that is coveted by the Turkish-backed Euphrates Shield alliance. A commander from the Syrian Democratic Forces (SDF), the YPG-led multi-ethnic group that is currently fighting Islamic State militants in Raqqa, told Al-Monitor that the Turkish-inspired operations against the YPG were being directed from an area 6 kilometers (roughly 4 miles) south of the alliance-held town of Azaz.

“The YPG encircled the group and killed and wounded many of them,” said the commander, speaking on condition of anonymity. These claims were echoed by Rojhat Roj, a YPG spokesman who called the Turkish-backed rebels “mercenaries.” In a separate statement, the YPG said the attack had been successfully repelled by its allies in Jaish al-Thuwar. "The Defense Units in Rojava [northern Syria] have said repeatedly that they do not wish to fight Turkey or its proxies, but once attacked we will use our right of self defense, period."

At the same time, Turkish forces reportedly kept up a barrage of artillery attacks targeting the YPG-controlled enclave of Afrin. The Syrian human rights group said Turkish forces had fired on the outskirts of the city and its environs for a second consecutive day, causing fires and other material damage. Thousands of residents infuriated by the deaths of a woman and her two children allegedly as a result of Turkish actions have taken to the streets in Afrin. The pro-Turkish daily Sabah confirmed that Turkish shelling of YPG positions was ongoing, labelling it a response to YPG aggression. It remains unclear whether Turkish forces were firing from across the border or from within Syria.