At least 160 people have been killed after an earthquake of 6.4 magnitude hit Balochistan province in south-western Pakistan.
The tremor struck 70km north of Quetta at 4.09am local time on Wednesday, the US Geological Survey said. Officials say there have been at least three aftershocks.
Many houses collapsed during the quake and some were destroyed in landslides that followed it. Officials said the death toll was expected to rise.
Teams of army and paramilitary Frontier Corps troops are in the area, helping to rescue the injured and retrieve bodies.
Senior army official Major General Salim Nawaz said the area remained accessible for convoys carrying relief material.
However, the mountainous region is thinly populated and local infrastructure is poor, making it difficult to get a clear picture of the casualties.
Provincial Revenue Minister Zamrak Khan said many affected areas had still not yet been reached.
The worst-hit area appeared to be Ziarat, about 50km north of Quetta, where hundreds of mostly mud and timber houses had been destroyed in five villages, mayor Dilawar Kakar said.
He said some homes were buried in a landslide triggered by the quake. Hundreds of people had been injured and some 15,000 made homeless.
"I would like to appeal to the whole world for help. We need food, we need medicine. People need warm clothes, blankets because it is cold here," he said.
Nearby Pishin district was also hit.
Pakistan is no stranger to natural disasters. In October 2005, about 73,000 people were killed when a 7.6-magnitude quake hit northern mountains, and last year the worst floods on record in Balochistan killed hundreds.
Quetta itself was largely destroyed and about 30,000 people were killed in a severe earthquake in 1935.
Large parts of south Asia are seismically active because a plate known as the Indian plate is pushing north into the Eurasian plate.
Balochistan is Pakistan's largest province but its most thinly populated. It has the country's biggest reserves of natural gas but there were no reports of damage to gas facilities.