State television said more than 336 people were killed in Iran and at least 3,950 were injured. Local officials said the death toll would rise as search and rescue teams reached remote areas of Iran.
The earthquake was felt in several western provinces of Iran, but the hardest hit province was Kermanshah, which announced three days of mourning. More than 236 of the victims were in Sarpol-e Zahab county in Kermanshah province, about 15 km (10 miles) from the Iraq border.
Iranian state television said the quake had caused heavy damage in some villages where houses were made of earthen bricks. Rescuers were laboring to find survivors trapped under collapsed buildings.