Aid agencies brace for Afghan exodus

ISLAMABAD, Pakistan (CNN) -- Vast groups of refugees, possibly numbering in the tens of thousands, are continuing to try to leave Afghanistan as fear grows of possible U.S. strikes.

On Wednesday, Pakistan announced that although it was refusing to reopen its border with Afghanistan it would aid those that cross illegally.

Aid agencies are warning of a "humanitarian catastrophe" if, as predicted, some 1.5 million Afghans attempt to cross the border into neighboring Pakistan or Iran.

The United Nations says years of conflict, severe drought, human rights abuses and "significant population movements" have left more than 5 million Afghan civilians, mostly women and children, with "a fragile grip on survival."

It has called on countries bordering Afghanistan to ensure their borders are open to civilians seeking refuge "in accordance with international law".

On Tuesday, discussions between the Pakistani government and the U.N. about opening one of two main border crossings fell through, although a few people with visas were allowed to pass into Afghanistan.

VIDEO CNN's Tom Mintier reports on agencies getting ready for the influx of refugees into Pakistan. (September 24) Play video (QuickTime, Real or Windows Media)    Refugee facts Over 5 million Afghans in need of aid to survive Tens of thousands on the move in search of safety Many more unable to travel Nearly 20 percent of those in need are children under age 5 Source: United Nations and U.N. agencies

Meanwhile, Pakistani sources have told CNN a new refugee camp has been set up near the border with Afghanistan.

Officials say they did not want to increase the size of existing camps because they were of a manageable size.

New camps

On Tuesday, the United Nations High Commissioner for Refugees (UNHCR) ordered 20,000 tents into the area to shelter up to one million refugees if necessary.

In Iran, which borders Afghanistan to the north, UNHCR and Iranian government officials have identified 12 sites for possible refugee camps along the border.

The U.N. agency also said it had received pledges of $6.8 million in start-up funds to finance the establishment of a large-scale relief operation to tackle the influx of Afghan refugees.

In Afghanistan itself, there are concerns about getting humanitarian aid to where it is needed.

Many agencies, including UNICEF, are talking about positioning the aid along the border and then pushing it across to Afghan staff members of the aid groups so the aid can be distributed.

The ruling Taliban government in Afghanistan shocked aid agencies Tuesday when it confiscated 1,400 tons of supplies from the World Food Program, shut down its facilities in the country and put them under guard.

UN warning

WFP officials said they would look for alternative ways to get the food cross the border from Pakistan.

The U.N. meanwhile has warned warring parties in Afghanistan not to target or otherwise block aid supplies from reaching those in need.

"Those who deliberately hold food from starving people, attack and impede humanitarian relief workers, whether local or international, should know that the international community will hold them responsible," spokesman Fred Eckhard said.

Last Friday, the Taliban locked and sealed communication equipment at UN offices across the country.

Officials say they do still have communications with local workers in some areas -- although for security reasons they won't say where.

-- CNN's Tom Mintier in Islamabad and Liz Neisloss at the U.N. in New York contributed to this report