Hundreds of thousands of Pakistanis have fled fighting between the army and Taliban militants in a northwestern valley, raising the risk that public support could turn against an offensive Washington sees as a must-win battle.

The U.S. announced $4.9 million worth of aid for the refugees, many of whom arrived Monday in parched camps where children held empty food bowls and men lined up in the baking sun, questioning how they would survive.

At least 360,000 Pakistanis displaced by recent fighting have registered in camps and other centers since early May, the U.N. said. That’s on top of some 500,000 people displaced by offensives that date to August 2008 — though it’s unclear how many of those remain refugees.