More than 100 people were killed when a strong earthquake struck southwestern Pakistan on Wednesday bringing down hundreds of houses.

The toll was expected to rise, a provincial government minister said.

"More than 100 people have been killed and the death toll is expected to rise," said Provincial Revenue Minister Zamrak Khan. "Eight villages in Ziarat have been badly affected and there are still many areas which have not yet been reached," Khan told Reuters.

Ziarat is a scenic valley, one of Baluchistan province's main tourist spots, 70 km (45 miles) northeast of the provincial capital, Quetta.

The US Geological Survey said a 6.4 magnitude quake hit the region before dawn.

The Pakistan Meteorological Department put the magnitude at 6.5 and said the quake struck at 5.10 am (2310 GMT). The epicentre was near Ziarat.

"About four villages were severely hit. Over 90 percent of houses have been destroyed and some people are still trapped under the debris," said Sohail-ur-Rehman, a top district administration official in Baluchistan.

"In two villages, Wam and Warchu, we have reports of 80 dead but the toll is bound to be higher as we haven't been able to reach the other two villages," Rehman told Reuters by telephone. Army helicopters had arrived to help with the rescue, he said.

Officials in Ziarat said many houses had collapsed and some had been destroyed in landslides trigged by the quake. "Hundreds of mud houses have collapsed. We are using whatever resources we have to help the people and have asked for help from the provincial government," said Ziarat district chief Dilawar Khan. "There is a large number of injured."    

Teams had yet to reach some remote places in mountains above the Ziarat valley, he said. Ziarat district has a population of about 50,000.

Five people had been killed in neighbouring Pishin district, to the north of Quetta, district government officials said.

"We were fast asleep when the tremor struck. We grabbed the  children and ran outside. The earth continued shaking for more than a minute," said Habibullah, a resident of Pishin.

He said no one had been hurt in his neighbourhood which was being hit by aftershocks.

The head of a national disaster management team, Farooq Ahmed Khan, said about 300 rescue workers had reached Ziarat. The army was sending a field hospital while tents, blankets and clothing were also being flown in. - Reuters