Disaster management officials have said the death toll could rise, Geo News reported.
Islamabad’s National Seismic Monitoring Center reported that the quake’s epicenter was near Harnai, at a depth of about 15 kilometers. He added that the “exact damage” had not yet been confirmed.
The earthquake affected Quetta, Sibi, Harnai, Pishin, Qila Saifullah, Chaman, Ziarat and Zhob in Balochistan.
Most of the deaths and injuries were reported in the remote northeastern district of Harnai.
The US Geological Survey said it was a magnitude 5.9 earthquake that struck at shallow depth. Shallow earthquakes can cause more damage.
The death toll of 20 was confirmed by Harnai District Deputy Commissioner Sohail Anwar Hashmi.
The Provincial Disaster Management Authority (PDMA) said many of the dead were women and children.
Images on social media showed residents of the town of Quetta on the streets in the aftermath of the quake, the Dawn newspaper reported.
Aftershocks are still being felt in different regions. The first tremors were felt at 3:20 a.m., after which panicked citizens rushed out of their homes reciting verses from the Holy Quran. Relief and rescue activities are ongoing, with an emergency declared in all hospitals.
Several people were rushed to hospital in critical condition, Hashmi said. He said several buildings in Harnai were damaged. Many people remained buried under the rubble.
More than 100 mud houses also collapsed, leaving hundreds of people homeless.
Power to the area has been suspended, he said.
Balochistan Chief Minister Jam Kamal Khan Alyani said relief and evacuation efforts were underway.
“Blood, ambulances, emergency aid, [helicopters] and rest, all things are placed … All departments are working on it, “he tweeted.
Speaking to Geo News, PDMA chief executive Naseer Ahmed Nasir said there had been landslides in mountainous areas.
Interior Minister Mir Ziaullah Langove said five to six districts were affected on a “large scale” and data was still being collected.
Pakistan straddles the Indian and Eurasian tectonic plates and is located on the Indus-Tsangpo suture zone, about 200 km north of the Himalayan front, making this region very susceptible to earthquakes.
The region has the highest seismicity rates and the largest earthquakes in the Himalayan region, caused mainly by movement over the thrust faults. The country has suffered several earthquakes in recent years.
One of the worst earthquakes to hit the country in recent years occurred on October 8, 2005, which killed more than 74,000 people.