The death toll from Monday's earthquake and aftershocks that hit Turkey and Syria has surpassed 8,300, as desperate efforts continue to rescue people trapped under rubble.

A powerful quake with a magnitude of 7.8 hit southern Turkey near the Syrian border early on Monday, followed by another major quake and a series of aftershocks.

Turkey's government says it has confirmed 5,894 deaths and more than 34,000 injured in the country, and the collapse of over 5,700 buildings.

Syria's health ministry says it has confirmed 1,250 deaths, mainly in the country's northwest. At least 1,220 others have died in areas controlled by anti-government forces, according to a group conducting rescue operations in those areas.

Istanbul Mayor Ekrem Imamoglu tweeted early on Wednesday that rescuers saved a Syrian boy from under rubble in Hatay province near the Syrian border. Video posted along with the tweet shows a rescuer using the cap of a plastic bottle to give the boy water.

Rescuers are rushing to find survivors. The survival rate in disasters is said to drop after 72 hours, which is fast approaching.

But there are concerns that efforts to access the disaster-hit areas will be hindered due to damaged roads and a lack of vehicles for rescuers.