Syrian activists say a government airstrike has killed 10 civilians in a rebel-held town in the country's north.

Two activist groups — the Aleppo Media Center and the British-based Syrian Observatory for Human Rights — said Tuesday that the dead in the strike on the town of Bzaa included children.

The strike happened on Monday. The town of Bzaa lies in a rebel-held area of the northern Aleppo province.

Activists say Syrian forces loyal to President Bashar Assad have killed hundreds in bombing of rebel-held areas there in recent weeks.

The strike came amid the most serious infighting between Syrian rebels in the north. Activists say rebel-on-rebel clashes intensified Tuesday, as an alliance of opposition brigades tries to rout fighters from an al-Qaida-linked group from the north.