Activists and residents of Syria's ancient city of Palmyra say days-long government airstrikes targeting the area controlled by the Islamic State group have forced hundreds of residents to flee.

A city resident says the bombardment, which included dropping barrel bombs, continued for the third straight day on Thursday, without any let up as Muslims started marking the first day of the Eid Al-Adha holiday.

He says there is a severe shortage of medical supplies and that hundreds of the few remaining residents fled in the early morning to Raqqa — another IS-controlled city about 270 kilometers (170 miles) from Palmyra.

The resident spoke on condition of anonymity because he feared for his safety.

The Britain-based Syrian Observatory for Human Rights also reported airstrikes on Palmyra for the past three days.