A major earthquake of magnitude 7.8 and its powerful aftershocks have killed nearly 1,600 people and injured thousands in southeastern Turkey and northwestern Syria as buildings collapsed across the region, triggering searches for survivors in the rubble.

The initial earthquake hit near the Turkish city of Gaziantep 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 as far as Cyprus, Egypt and Lebanon. It was later followed by another heavier one.

Search and rescue teams were immediately dispatched to the areas hit by the earthquake. Turkey’s defence ministry said the country’s armed forces have established an air corridor to enable medical and rescue teams to reach the earthquake-hit areas.

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 harrowing images of 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.

In Syria, state media reported that at least 326 people have been killed and some 1,000 injured after numerous buildings tumbled down.

In the Syrian capital, Damascus, buildings shook and many people rushed onto the streets in fear.

The earthquake jolted residents in Lebanon from their beds, shaking buildings for about 40 seconds. Many residents of Beirut left their homes and took to the streets or got in their cars to drive away from buildings.

A number of international leaders swiftly offered assistance. Russian President Vladimir Putin, who maintain ties with both Turkey and the Syrian government, sent his condolences and support to both Erdogan and Assad.

French President Emmanuel Macron also said his country was ready to provide emergency aid to Turkey and Syria.

Ten search and rescue team from eight European Union countries have been mobilized to help first responders in Turkey, the European Commission said in a statement.

The units come from Bulgaria, Croatia, the Czech Republic, France, Greece, the Netherlands, Poland and Romania. Italy and Hungary have also offered to send teams to Turkey, the commission wrote.