Officials say dozens injured after magnitude 5.9 quake struck remote Harnai while many people were sleeping.
At least 20 people have been killed and more than 200 injured when a magnitude 5.9 earthquake struck southwestern Pakistan in the early hours of Thursday as people slept, the Disaster Management Authority said.
Rescue workers said most of those killed were women and children.
The earthquake struck at the relatively shallow depth of 20 km (12 miles) with an epicentre 102 km (62 miles) east of the city of Quetta, the US Geological Survey (USGS) said.
More than 100 mud houses collapsed and many buildings were damaged.
As rescuers searched through the rubble, some of the injured were treated on stretchers in the street under telephone torchlight.
“The earthquake struck at around 3am. The seriously injured people are in hospital and they are waiting for ambulances to be moved to Quetta,” said resident Muzaffar Khan Tareen.
An army helicopter airlifted at least nine of the seriously injured to Quetta, the state-run Associated Press Pakistan reported.
Aftershocks were being felt across the region.
Pakistan sits on top of colliding tectonic plates and earthquakes are common.
A magnitude 7.7 earthquake hit Quetta in 1935, killing between 30,000 and 60,000 people and destroying much of the city.
In 2005, about 73,000 people were killed by a magnitude 7.6 quake that struck about 95km (59 miles) northeast of the capital, Islamabad.