The army has reached some survivors but thousands still await relief

Up to 50,000 people may be homeless in Balochistan province following the 6.4 magnitude tremor. The official death toll has risen slightly to 215.

As well as shelter, villagers lack basic supplies, like blankets and food.

The quake comes as Pakistan's civilian government faces al-Qaeda and Taleban attacks, as well as an economic crisis.

Military helicopters are being used to reach mountainous and remote locations, where some villages have been cut off by landslides.

The army has airlifted supplies and medical teams to Ziarat district, where hundreds of mostly mud and timber houses have been destroyed in a number of villages.

The quake crushed hundreds of vulnerable houses

The International Committee of the Red Cross said it was handing out some 2,500 tents, while a medical team with one tonne of supplies was helping at overcrowded hospitals.

The BBC's Ilyas Khan in Karachi says the amount of relief being delivered is not enough as the number of people left homeless by the quake is estimated between 35,000 to 50,000.

"We had so few blankets to cover ourselves during the night that we only had one between six children," farmer Shahnawaz Khan told AFP news agency in the remote south-western village of Kan Bangla.

Neighbouring India and the US have also offered help, while the UN World Food Programme pledged to supply emergency rations to survivors for two months.

Little hope

Rescue workers have said there is little hope of finding survivors in the debris. The early hours quake just north of Quetta buried villagers as they slept.

Many of the survivors have dug mass graves for their dead in the worst-hit areas.

Activists with hard-line Islamic organisations were first to reach some of the most remote parts with relief supplies.

Among them was Jamaat-ud-Dawa, designated a terrorist group by the US government for links to Kashmiri Muslim separatists.

The same group also helped survivors of a huge quake that devastated northern Pakistan in October 2005, killing up to 80,000 people.

Balochistan is home to a long-running separatist movement, but has so far been spared the level of violence seen in the north-western tribal areas bordering Afghanistan, say correspondents.

In 1935, Quetta suffered almost complete destruction in an earthquake which claimed the lives of about 30,000 people.

Pakistan sits atop an area of seismic collision between the Eurasian and Indian tectonic plates, the same force that created the Himalayan mountains.