Rescuers struggled through waist-deep snow Saturday to reach people trapped by an earthquake that killed at least 300 people and injured more than 500, officials said.

Hundreds of people were believed trapped in remote mountain villages where frail straw and mud huts were flattened by the powerful quake, which rumbled across Afghanistan and Pakistan before dawn Friday.At least 300 homes in the village of Arandu in the foothills of the Himalayas were destroyed by the temblor, said Abdul Sattar Edhi, who operates a Karachi-based emergency relief organization.

Snow, rock slides and avalanches made some of the narrow and treacherous roads into the region impassable, officials said.

"We don't know how many people are dead or injured. We've sent warm clothes, blankets and medicine, but the problem is access," Edhi said.

Officials in Pakistan said the number of dead and injured was still unclear because the worst-hit areas were in remote and rugged mountainous regions of the Northwest Frontier Province bordering Afghanistan.

The official death toll stood at 164, although government officials said the number was at least 300 and would likely rise.

About 2,000 houses collapsed in the quake that registered 6.8 on the Richter scale, authorities said.

"I was sleeping when I woke to people screaming. Women and children were begging for help," said Haji Jehanzeb, whose village of Sultan was violently shaken.