"This is a massive, massive displacement," said Sebastien Brack, an official with the International Committee of the Red Cross who is based in Islamabad. "This is a serious humanitarian crisis developing."

President Obama brought together the presidents of Pakistan and neighboring Afghanistan on Wednesday in an effort to overcome friction with the new administration in Washington over how to combat the growing power of Taliban fighters and their Al Qaeda allies.

James L. Jones Jr., Obama's national security advisor, said Pakistani President Asif Ali Zardari made a forceful pledge to combat extremism. But White House officials said they received no promises that Pakistan would deploy more troops against the militants.

Each new offensive by Zardari's army in recent weeks through the Buner and Dir districts, which abut the Swat Valley, has led to a fresh exodus of civilians.

The launch Wednesday of another military operation has officials predicting another wave of refugees. Reports said 47 militants, 15 security personnel and 36 civilians were killed Wednesday in Swat and the wider Malakand region.

Militants reportedly laid mines in Mingora, Swat's main town, and looted several banks before setting them ablaze as helicopter gunships and artillery pounded their positions.

Civilians poured out of the valley and thousands of others holed up because of nearly round-the-clock curfews imposed by authorities.

In February, local officials granted Taliban militants the right to impose Sharia, or Islamic law, in the Malakand region in return for agreeing to put down their weapons. But the armed militants soon spread into neighboring districts, prompting the army to act.

Aware of the growing humanitarian crisis on its hands, the government said Wednesday that it would allocate $60 million for the displaced. Top army brass, the prime minister and various national and provincial agencies held high-level meetings on the issue.

But critics say Pakistan has a history of programs that sound impressive but succumb to bureaucracy or corruption.

"There's a big gap between announcements and what we see at ground level," said Iqbal Khalil, an official with the Al Khidmat Foundation, an Islamic fundamentalist charitable organization.

Even before the latest fighting, the United Nations said 450,000 to 500,000 people had fled their homes over the last 18 months in the Swat Valley, areas around Peshawar, and elsewhere in the mountainous North-West Frontier Province, as the Taliban's grip has expanded.

An estimated 200,000 more fled last month, and a full-fledged military assault in Swat could add several hundred thousand.

Many of the displaced end up going to Mardan, a half-hour drive from Peshawar, instead of heading farther away from the Afghan border to Islamabad. The strength of the Taliban and its Al Qaeda allies along the Afghan frontier has led to frequent military clashes and missile strikes by U.S. drone aircraft.

Mardan already has three displacement camps and three more are under construction.

At the Sherkh Shehzad tent village on the outskirts of Mardan, on a several-acre site flattened for a housing complex, organizers hand out blankets and water buckets to arriving families.

"We walked for two days and one night, almost 40 miles," said Durrani Wazir, a 63-year-old farmer, his back stooped from years in the fields and his white prayer cap dirt-stained from the journey. "I just want to get back to my village. God knows when that will be."

Once they're inside the camp, the government has tried to make the evacuees feel safe. Two guards are posted near the entrance. Although they're not armed, they say they have weapons in a nearby tent.

"I'm responsible for protecting these people at night," said Mohammed Naseem, a civil defense volunteer in an oversized black uniform. "I'm not scared. Everyone has to die someday."

The camp housed 1,246 people Wednesday, up from about 1,000 the day before. A nearby camp holds 50,000.

Despite the huge numbers of displaced people, aid officials say Pakistan has some advantages over other countries suffering such crises.

The ethnic Pashtun communities, from which the Taliban draws much of its local strength, also bear the brunt of the fighting, and are relatively cohesive. Most of the displaced have shunned the camps in favor of friends' or relatives' hujras, or traditional guesthouses.

"This is part of our culture and religious responsibility, to open our hujras and provide protection to those in trouble," said Mohammed Wakeel, a government employee in Mardan.

And overall, Pakistan is far less impoverished than countries in Africa or on other continents where war or famine has led to mass displacements.

On the other hand, adding to the challenge is a lack of coordination among government agencies, critics said. The army's penchant for secrecy means it doesn't share information on the timing of its offensives with local officials -- limiting the effectiveness of their response.

Shopkeeper Bakht Hassan said he hadn't planned to leave his home in the Buner area until Friday, when local authorities told everyone to get out.

Hassan rushed home to arrange transportation. But everyone was doing the same, so all he could find was a tractor. He paid its driver the equivalent of $8 and piled his wife and children on. As they left, military helicopters appeared and opened fire on the militants, he said.

Now he's living with 36 members of his extended family in two mud rooms in Rustam on the Buner border.

"We brought hardly any clothes or other belongings in our haste to save the women and children," he said.

Those on the humanitarian front lines warn that the displaced are angry and traumatized, enduring long days in hot tents with little to do but grow more frustrated.

"Displaced people are sources of instability," said Manuel Bessler, head of the U.N. Office for Coordination of Humanitarian Affairs in Pakistan. "The situation creates tension and is obviously not sustainable."

There was a near-riot Tuesday over registration procedures in a Mardan camp.

Muhammad Irfan Chaudary, a spokesman for the National Disaster Management Authority, said those complaints have been addressed and that the government is able to handle the large numbers.

Many of the displaced have seen fighting overwhelm their quiet villages and struggled mightily to get to Mardan.

Many also seem to blame the army at least as much as the Taliban, a political problem for the government.

Hassan, the shopkeeper, said he was more afraid of indiscriminate fire from the military than he was of the Taliban.

"The army got everyone into great trouble," he said. "Our lives have been turned into hell."

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Ali is a special correspondent. Special correspondent Mubashir Zaidi in Islamabad contributed to this report.