BEIRUT (AP) — A Syria war monitoring group says an overnight missile attack in the country's northern region has killed 26 pro-government fighters, mostly Iranians.

The Britain-based Syrian Observatory for Human Rights says the attack appears to have been carried out by Israel and targeted an arms depot for surface-to-surface missiles at a base in northern Syria known as Brigade 47. The Observatory says four Syrians were also among casualties.

Tehran has sent thousands of Iran-backed fighters to back President Bashar Assad's forces in the country's seven-year civil war.

Earlier on Monday, Syrian TV reported a "new aggression," with missiles targeting military outposts in northern Syria.

The state-run television reported that the missiles targeted military outposts in the Hama and Aleppo countryside.