Aid workers say conditions in many of the areas of northern Pakistan devastated by last week's earthquake are getting worse, not better. The Red Cross is warning that thousands of families may be cut off by winter weather and will need stockpiles of emergency supplies to survive the harsh conditions.

Relief workers in quake-hit communities in Pakistani say the scale of the emergency - rather than coming under control - continues to grow.

The death toll, upwardly revised nearly every day, is approaching 50,000 in Pakistan alone and officials say cold weather and untreated injuries could push that number higher.

In the hardest hit areas of Kashmir and the Northwest Frontier Province, relief workers say the priority now, as it has been for nearly a week, is shelter.

Stephen Matthews, with U.S. aid agency World Vision, says unless winter tents reach quake-stricken areas soon, there could be a second catastrophic loss of life.

"It is getting colder by the day in this part of the world," he explained. "There are people living outdoors, literally hundreds of thousands of them and, if we don't get in there, we're going to have people dying from freezing cold."

Mr. Matthews says the international community must continue to support relief operations in the area.

"I just cannot state enough how grave the situation is here and how the world needs to continue to pay attention to what is happening here," he said.

The United Nations says the earthquake left more than three million people homeless and 300,000 winterized tents are needed, but fewer than 40,000 units have been delivered.

The United Nations also says half a million people have not received any emergency aid at all.

Many of them are still trapped behind landslides, which have blocked roads to more than 900 villages in remote Himalayan valleys.

For now, helicopter airlifts are the only way to get aid through and evacuate the wounded.

More than 60 helicopters were flying missions Tuesday, including choppers sent by the United States and Germany.

But the International Red Cross says winter weather could strand more than 10,000 families in several dozen isolated villages until January or February.

Relief workers are racing to provide the remote villages with a three-month stockpile of food before winter arrives.

Emergency medical camps are also being set up in several forward locations and larger field hospitals are being built in some of the larger towns and cities.

But relief agencies say it will be days, perhaps weeks before those facilities become fully operational.

Until then, they say, all they can do is to focus on the people they can help, while hundreds of thousands of others go unaided.