Officials in the Baluchistan Province near the Afghan border expect the death toll to rise significantly, as reports come in from remote regions.
The quake struck at 4:09 a.m. local time (23:09 GMT Tuesday), 70 km (45 miles) north of the provincial capital Quetta, the U.S. Geological Survey said. Several aftershocks have since been felt.
Pakistan's military has sent helicopters to the Baluchistan Province, carrying rescue and medical teams, as hospitals struggle to cope with the large numbers of injured.
Convoys carrying aid for the victims face difficulties in reaching many of the remote villages in the impoverished mountainous region.
The worst-hit area appeared to be the Ziarat district, where numerous mud houses were destroyed. Mayor Dilawar Kakar said several houses had been buried in a landslide. He put the number of injured at several hundred, and said thousands have lost their homes.
