At least 29 people have been killed in fighting between Kurdish and Al-Nusra Front fighters in northern Syria in the past two days, the Syrian Observatory for Human Rights said Thursday.

At least 19 Al-Nusra Front 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 erupted after Al-Nusra Front militants attacked a convoy of Kurdish women fighters, Observatory director Rami Abdel Rahman said.

Elsewhere in the country, the Observatory reported five killed in an air strike on the town of Saraqeb north-western Idlib province.

The group said at least four missiles fired by regime war planes hit residential buildings, killing five civilians and injuring dozens more.

At least 120 people were killed throughout Syria on Wednesday, according to the group, including 42 civilians, 61 rebels and 17 soldiers.

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.