BEIRUT (AP) — The Syrian government and an opposition monitoring group have condemned what they call Turkey's "crimes" against the Syrian people in the northern town of al-Bab that is controlled by the Islamic State group.

Turkish troops and allied opposition fighters have been on the offensive in al-Bab for weeks trying to take it from IS, a battle that has killed hundreds of people so far.

The Syrian Observatory for Human Rights said Turkish shelling and airstrikes have killed 45 people in al-Bab since Wednesday.

Turkey wants to clear the area near its border of IS militants.

The Syrian Foreign Ministry on Friday condemned what it called Turkey's violations of Syria's sovereignty.

The condemnation was expressed in two letters addressed to the U.N. Secretary-General and President of the Security Council.