The major 7.8-magnitude earthquake that struck Turkey and Syria on Monday, killed more than 3,000 people and flattened thousands of buildings as rescuers dug with bare hands for survivors.

Multi-story apartment buildings full of residents were among the 5,606 structures reduced to rubble in Turkey, while Syria announced dozens of collapses, as well as damage to archaeological sites in Aleppo.

The head of Syria's National Earthquake Center, Raed Ahmad, called it "the biggest earthquake recorded in the history of the center."

The initial quake was followed by dozens of aftershocks, including a 7.5-magnitude tremor that shook the region.

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Despite temperatures falling below zero, frightened residents in the city were preparing to spend the night on the streets, sitting around fires for warmth.

At least 1,293 people died across Syria, the government and rescuers said.

Turkish government officials reported another 1,762 deaths, putting the combined total at 3,055. Ankara declared seven days of mourning for the dead.

The rescue was being hampered by a winter blizzard that covered major roads in ice and snow. Officials said the earthquake made three major airports in the area inoperable, further complicating deliveries of vital aid.

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Monday's first earthquake struck at 4:17 am (0117 GMT) at a depth of about 18 kilometers (11 miles) near the Turkish city of Gaziantep, which is home to around two million people, the US Geological Survey said.

Denmark's geological institute said tremors reached the east coast of Greenland about eight minutes after the main quake struck Turkey.

More than 12,000 people are injured in Turkey, the disaster management agency said, while Syria said at least 3,411 people were injured.

Some of the heaviest devastations occurred near the quake's epicenter between Kahramanmaras and Gaziantep, where entire city blocks lay in ruins under gathering snow.

A famous mosque dating back to the 13th century partially collapsed in the province of Maltaya, along with a 14-story building with 28 apartments that housed 92 people.

The Syrian Health Ministry reported damage across the provinces of Aleppo, Lattakia, Hama, and Tartus. Officials cut off natural gas and power supplies across the region as a precaution, also closing schools for two weeks.

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Turkey is in one of the world's most active earthquake zones. The country's last 7.8-magnitude tremor was in 1939 when 33,000 died in the eastern Erzincan province.

The Turkish region of Duzce suffered a 7.4-magnitude earthquake in 1999 when more than 17,000 people died.

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