More than 800 people have been killed - and nearly 3,000 injured - after a magnitude-six earthquake struck eastern Afghanistan just before midnight on Sunday, the United Nations' humanitarian agency has said.

Most of the deaths are in Kunar province, officials say, warning that the death toll may rise significantly as entire villages have been destroyed by the quake. The epicentre is in a remote mountainous area, making it difficult for rescue operations to be carried out. The scale of devastation is unimaginable, a Taliban official said.

The disaster comes as Afghanistan reels from a severe drought, aid cuts and what the World Food Programme describes as an unprecedented crisis of hunger.

The earthquake hit at 23:47 (19:47 GMT) on Sunday, some 27km (17 miles) east of Jalalabad - the country's fifth-largest city, in eastern Nangarhar province. Faridullah Fazli was fast asleep at home in Asadabad, on the banks of the Kunar river, and the tremor jolted him awake. There was a very strong earthquake, accompanied by sounds that were very scary, he told the BBC. We didn't sleep until morning. After the earthquake, there were small tremors, and there are still.

Fazli said he went to the clinic in town, helping transport the dead and wounded into ambulances to be taken to a hospital further south in Nangarhar province. It was a very scary situation, just an atmosphere of fear and terror, Fazli said.

A resident of Mazar Dara, in the Nurgal region, estimated that 95% of the village had been destroyed, with five to ten injured individuals in every household.

The worst damage was in Kunar—a rugged, mountainous region with limited farmland. With roads blocked, rescue operations can only be carried out by air. More than 100 flights have been conducted since the earthquake, but many still remain unrescued beneath the rubble.

The Taliban government launched an appeal for assistance as Afghanistan continues to face significant humanitarian challenges exacerbated by ongoing conflict and natural disasters.