A rescue operation is under way across much of southern Turkey and northern Syria following a huge earthquake that has killed more than 1,000 people.

The 7.8 magnitude quake struck near Gaziantep in the early hours of Monday while people were asleep.

A new 7.5-magnitude tremor hit at around 13:30 local time (10:30 GMT), which officials said was "not an aftershock".

Turkey's President Erdogan said 912 people had been killed in Turkey alone after the first quake, with more than 5,300 wounded.

Syrian authorities are reporting more than 370 deaths.

Rescuers are racing to save people trapped beneath the rubble after hundreds of buildings collapsed in both countries.

World leaders have pledged to send aid after Turkey issued an international appeal for help.

Millions of people across Turkey, Syria, Lebanon, Cyprus and Israel felt the earthquake. (BBC)