Update : At least 20 killed and over 100 injured in Afghanistan quake

Officials tell the BBC that at least 20 people have been killed and more than 100 are being treated at hospitals for injuries

Dozens of houses are "under rubble", say multiple sources from the Taliban government, and it is feared that the death toll could rise

Taliban government officials have urged humanitarian organisations to aid the rescue effort in remote mountainous areas - some are only accessible by air due to landslides and flooding

The quake has shaken buildings from Kabul to Pakistan's capital Islamabad - which is more than 300km (186 miles) away.

Two sources in Kunar province tell me that at least four helicopters carrying medical staff arrived in Mazar valley in Kunar province early this morning.

This is the most devastated area where roads have been blocked by landslides.

The medical staff will first try to treat wounded, and the critically injured will be airlifted to the capital Kabul or nearby hospitals.

However, given the scale of the devastation, officials say a lot more help would be urgently required.