Hours after a massive earthquake struck Pakistan, killing thousands of people and injuring several hundreds, United Nations' child agency UNICEF said it has begun moving relief supplies to affected areas.

The supplies include blankets, clothing, tents, emergency medical supplies, food for infants and water purification tablets, UNICEF Executive Director Ann Veneman said late on Saturday night.

UNICEF expects heavy casualities among children as one-fifth of the region's population is under five years of age.

"Children in the affected areas will be vulnerable to hunger, cold, illness, and trauma," Veneman said, adding, "Getting immediate life-saving relief into the region will be our priority for the next hours and days, even as the search and rescue effort goes on."

UNICEF will work closely with the Pakistan government to determine what additional relief supplies are needed, the agency said.

Teams from UNICEF's Peshawar office are being deployed into the countryside as part of a joint UN response team and the agency is standing by to mobilize needed supplies from its operations elsewhere in the region and from its global supply hub in Copenhagen, Veneman said.

Over 3,000 people, nearly 1600 in hardest-hit NWFP and about 1200 in Pakistan-occupied Kashmir, were killed in the killer quake, which triggered landslides, reduced villages to rubble and toppled hundreds of buildings.