Aftershocks and blocked roads were hampering efforts on Wednesday to help up to 15,000 people forced to sleep out in freezing temperatures in Pakistan's north following a major earthquake that killed 23 people last week. Government officials and aid workers said all aid, including tents, medicines, clothes and blankets, had to be airlifted on military helicopters to the affected villages because there was still no road access.

"It is the most serious problem and aftershocks are preventing us from clearing the roads," a government official told Reuters from the town of Chilas on the Karakorum Highway, linking the Pakistani capital, Islamabad, to China.

People were still afraid to live in their damaged houses and preferred to sleep outdoors, braving temperatures as low as minus four degrees Celsius, he said.

"Its getting colder each passing day," said resident Shaukat Ali.

More than 100 aftershocks have rocked the scenic mountainous region since last Thursday's quake. Four were recorded in the last 24 hours, of which two were about 4.0 on the Richter scale.

Shafiq-ur-Rehman, an aid worker with the British-based Islamic Relief group, said supplies were on their way to Chilas from where they would be airlifted.

Several aid organisations were working closely with the government to offer emergency aid, though there was still a big gap between what was required and what had been committed by the aid agencies, aid workers said.

Aid worker Iftikhar Khaled said 8,000 thick blankets were needed but only 2,450 were available.

Gilgit, the main town in the region about 250 km north of Islamabad, was facing shortage of fuel and some food items because of the closure of the Karakorum Highway, which was not damaged by the quake but has been blocked by landslides.

The first quake, measuring 5.5 on the open-ended Richter scale, hit at 2.22 a.m. on Thursday (2122 GMT Wednesday), destroying hundreds of homes and killing at least 23 people in three villages near the base of the famous Nanga Parbat peak in the Karakorum mountain range.

The epicentre was reported to have been around 48 km south-southeast of Gilgit.

The badly affected Astor valley region, which is behind Nanga Parbat -- at 8,125 metres the world's eighth highest mountain -- is a famous destination for mountaineers and trekkers but is prone to heavy seismic activity.

PHOTO CAPTION

Pakistani porters load an Air Force plane with earthquake relief goods in Rawalpindi in this November 22 photo. REUTERS/String