BEIRUT -- The U.S. military says it has struck an al Qaeda leadership and training facility in northern Syria where attacks threatening Americans and others were being planned.

The U.S. Central Command said in a statement that the strike occurred on Sunday near the northern province of Aleppo.

The Britain-based Syrian Observatory for Human Rights, an opposition-linked war monitor, said Monday that the strike killed eight members of the al-Qaida-linked Horas al-Din, which is Arabic for "Guardians of Religion."

The Observatory says the dead included six commanders: two Algerians, two Tunisians, an Egyptian and a Syrian.

Al-Qaida-linked militants control wide parts of northern Syria, mostly in Idlib province, the last major rebel stronghold in the war-torn country.