Soldiers and rescue teams on Wednesday stepped up their desperate search for survivors in the rubble of thousands of homes flattened by a powerful earthquake that struck Pakistan's Balochistan province as the death toll rose to nearly 350.

Official sources in Quetta, the capital of Balochistan, told that about 350 people were killed by the 7.7-magnitude quake, with a majority of deaths reported from the worst-hit Awaran district.

Maj Gen Muhammad Saeed Aleem, head of the National Disaster Management Authority, told reporters in Quetta he had information of 271 deaths and 246 injured. Other officials said 327 bodies were found in Awaran and Kech districts.

Officials said more people were feared to be buried under debris in far-flung areas which rescue teams had entered only today because of the difficult terrain and lack of roads.

According to official estimates, over 300,000 people in six districts were affected by the quake that hit yesterday afternoon. Many do not have access to food, drinking water or shelter and the situation was exacerbated by the hot weather.

Balochistan chief minister Abdul Malik Baloch has declared an emergency in Awaran and five other districts located near the epicentre.

Over 1,000 army and Frontier Corps personnel are involved in rescue operations and military officials said eight tonnes of food and medicines and six helicopters had been moved to the affected areas.

A large number of people were rescued from the debris of collapsed mud-brick houses and the injured were given emergency aid by military doctors and paramedics.

Residents of Awaran said no building in the town, including hospitals, schools and government officials, had remained intact.