A major earthquake of magnitude 7.8 struck central Turkey and northwest Syria, killing more than 500 people and injuring hundreds as buildings collapsed across the region, triggering searches for survivors in the rubble, www.aljazeera.com transmits.

The earthquake struck at 4:17am local time (01:17 GMT) on Monday, as people were sleeping, at a depth of about 17.9km (11 miles). It was also felt in Cyprus and Lebanon.

Turkey’s Vice President Fuat Oktay said 284 people had been killed and 2,323 people were injured, as authorities scrambled rescue teams and supply aircraft to the affected area while declaring a “level 4 alarm” that calls for international assistance.

Footage on broadcaster CNNTurk showed severe damage to the historic Gaziantep Castle.

Turkish President Recep Tayyip Erdogan said on Twitter that “search and rescue teams were immediately dispatched” to the areas hit by the earthquake. He also spoke by telephone with the governors of eight affected provinces to gather information on the situation and rescue efforts, his office said in a statement.

Turkish interior minister Suleyman Soylu said there had been at least six aftershocks and urged people not to enter damaged buildings due to the risks.

“Our priority is to bring out people trapped under ruined buildings and to transfer them to hospitals,” he said.

Videos shared on social media showed buildings reduced to piles of rubble in several cities in Turkey’s southeast.

Broadcasters TRT and Haberturk showed images of people gathered around destroyed buildings in the town of Kahramanmaras, looking for survivors. Other images showed people taking shelter in their cars on the side of snow-covered roads.