Residents were clearing the rubble of their destroyed homes in the Afghan province of Samangan on Monday, a day after a powerful earthquake shook the area.

At least 20 people were killed and more than 640 others injured, 25 critically, a disaster management official said.

Health officials said the numbers could rise.

Locals described waking up to polluted air and destruction, as they tried to save injured people and pulled out bodies from the rubble.

"I saw that everything was destroyed, people had suffered a lot of financial losses,' said resident Abdul Mubin.

The impoverished country often faces difficulty in responding to such natural disasters, especially in remote regions.

Buildings tend to be low-rise constructions, mostly of concrete and brick, with homes in rural and outlying areas made from mud bricks and wood, many poorly built.