Afghan earthquake: At least 280 killed and scores wounded, says state media
Pictures show landslides and ruined homes in eastern Paktika province, where rescuers are scrambling to treat the injured.
In remote areas, helicopters have been ferrying victims to hospitals.
The local Bakhtar News Agency said the death toll was likely to rise, adding more than 600 people were injured.
The quake struck about 44km (27 miles) from the south-eastern city of Khost shortly after 01:30 local time (21:00 Tuesday GMT).
"Unfortunately, last night there was a severe earthquake in four districts of Paktika province, which killed and injured hundreds of our countrymen and destroyed dozens of houses," government spokesman Bilal Karimi tweeted.
"We urge all aid agencies to send teams to the area immediately to prevent further catastrophe."
Taliban officials have called for aid agencies to rush to the affected areas in the nation's east.
Most of the casualties so far were in the Gayan and Barmal districts in Paktika, a local doctor told the BBC. Local media site Etilaat-e Roz reported a whole village in Gayan had been destroyed.
Tremors were felt across more than 500km of Afghanistan, Pakistan and India, according to the European Mediterranean Seismological Centre, quoted by Reuters.
The centre said that witnesses had reported feeling the quake in Afghanistan's capital, Kabul, as well as Pakistan's capital, Islamabad.
However, there have been no immediate reports of casualties, and the earthquake caused little damage in Pakistan, according to BBC Urdu. Read More…