Turkey’s President Recep Tayyip Erdogan has declared seven days of national mourning, and Syria has appealed to the United Nations for help following devastating earthquakes that killed more than 4,800 people and toppled buildings across southeast Turkey and northern Syria, writes Al Jazeera.

Authorities fear the death toll from Monday’s predawn magnitude 7.8 temblor, followed by a magnitude 7.6 earthquake and several aftershocks will continue to climb as rescuers looked for survivors among tangles of metal and concrete spread across a region already suffering under Syria’s 12-year civil war and a refugee crisis.

Rescuers searched through the frigid night into Tuesday morning, hoping to dig more survivors out of the rubble as those trapped cried out for help from beneath mountains of debris.

Orhan Tatar, an official with Turkey’s Disaster and Emergency Management Authority, gave the number of dead in the county at 3,381 on Tuesday morning, while 20,426 others were injured. Tatar said more than 5,700 buildings had also been destroyed.

In Syria, at least 1,444 people were killed and about 3,500 others were injured, according to the Ministry of Health and the White Helmets rescue organisation.