Rescuers in Afghanistan will try to reach isolated villages in the eastern region of Kunar, the epicentre of an earthquake that killed over 800 people and injured more than 2,800, authorities told Reuters on Tuesday.

Rescue operations were carried out in four villages in Kunar on Monday after the quake struck and efforts will now be focused on reaching more remote mountain areas, said Ehsanullah Ehsan, the provincial head of disaster management.

“We cannot accurately predict how many bodies might still be trapped under the rubble,” said Ehsan. “Our effort is to complete these operations as soon as possible and to begin distributing aid to the affected families.”

One of Afghanistan’s worst earthquakes, with a magnitude of 6, struck around midnight local time on Monday, at a shallow depth of 10 km (6 miles), killing 812 people in the eastern provinces of Kunar and Nangarhar.

Mountainous terrain and inclement weather have hindered rescuers reaching remote areas along the Pakistani border where the quake flattened mudbrick homes.

Gaining access for vehicles on the narrow mountain roads was the main obstacle for relief work, said Ehsan, adding machinery was being brought in to clear roads of debris.

On Tuesday, a line of ambulances was on the damaged mountain road trying to reach Kunar villages, as helicopters flew in, bringing aid supplies and taking the injured to hospitals, according to a Reuters witness.

Some of those injured have been transferred to hospitals in Kabul and the adjacent province of Nangarhar, said Ehsan.

Taliban soldiers were deployed in the area, providing help and security. The disaster has further stretched the war-torn nation’s Taliban administration, already grappling with a sharp drop in foreign aid and deportations of hundreds of thousands of Afghans by neighbouring countries.

“National and international organisations are present in the area, have organised their assistance, and, God willing, aid will be distributed in an orderly manner,” said Ehsan.

Rescue teams and authorities are trying to dispose of animal carcasses quickly so as to minimise the risk of contamination to water resources, a U.N. official said on Monday.

“Damaged roads, ongoing aftershocks, and remote locations of many villages severely impede the delivery of aid,” the World Health Organization said in a situation update, adding that over 12,000 people had been affected by the quake.

“The pre-earthquake fragility of the health system means local capacity is overwhelmed, creating total dependence on external actors,” said the update.

Afghanistan is prone to deadly earthquakes, particularly in the Hindu Kush mountain range, where the Indian and Eurasian tectonic plates meet.

A 6.1-magnitude earthquake that killed 1,000 people in the eastern region in 2022 was the first major natural disaster faced by the Taliban government.