A huge earthquake killed more than 3,700 people across a swathe of Turkey and northwest Syria on Monday, with freezing winter weather adding to the plight of the thousands left injured or homeless and hampering efforts to find survivors.

• The magnitude 7.8 quake brought down whole apartment blocks in Turkish cities and piled more devastation on millions of Syrians displaced by years of war.
• It struck before sunrise in harsh weather and was followed in the early afternoon by another large quake.