At least 29 people have been killed in fighting between Kurdish and jihadist fighters in northern Syria in the past two days, the Syrian Observatory for Human Rights said Thursday.
"At least 19 Al-Nusra Front (jihadist) fighters and 10 Kurds have been killed since the day before yesterday in clashes in the oil region of Hassakeh," the NGO said.
On Wednesday, the group said Syrian Kurdish fighters had pushed members of Al-Nusra and the Al-Qaeda-affiliated Islamic State of Iraq and the Levant out of the town of Ras Al-Ain and its nearby border crossing with Turkey.
The clashes between Kurdish fighters and jihadists erupted after Al-Nusra Front militants attacked a convoy of Kurdish women fighters, Observatory director Rami Abdel Rahman said.
Activists in Ras Al-Ain said members of the jihadist groups had taken advantage of the Muslim fasting month of Ramadan, which began last week, to try to impose their extreme version of Islam.
In the early days of the Syria conflict, when the opposition was desperate for help from any quarter, jihadist fighters were welcomed. But a spate of abuses has fuelled a major backlash.
The Observatory said that jihadist fighters began firing rockets at Ras Al-Ain, in western Hassakeh, after their expulsion.
They also attacked several roadblocks manned by Kurdish fighters and clashes were ongoing in the village of Tall Alu and Karhok in eastern Hassakeh, the group added.
Kurdish fighters, meanwhile, advanced elsewhere in the northeastern province, taking control of part of the Sweidiya area of Hassakeh, which is the only majority Kurdish province in Syria.
Syria's Kurdish minority have walked a sometimes ambiguous line in the country's conflict, which is now in its third year.
Despite occasionally cooperating with rebel fighters, the country's Kurds have largely chosen to remain outside the conflict, and have sought to keep both regime troops and rebels out of their areas.
Their position has earned them the ire of some rebels, who fault them for failing to back the uprising.
The community's more liberal interpretation of Islam has also made it a target for some extremist rebel groups, including Al-Nusra and the Islamic State of Iraq and the Levant.