Pakistan - The United Nations agency charged with looking after the welfare of children estimates that as many as one million women and children are internally displaced in Pakistan, following weeks of fighting between the Pakistani military and Taliban militants.

The United Nations Children's Fund (UNICEF)'s regional director Daniel Poole - during a visit to Jalala Camp, home to tens of thousands of internally displaced people (IDPs) - said the United States.

As part of that support, two US military planes touched down on Wednesday at an air base near Islamabad laden with air-conditioned tents and 120-thousand pre-packed meals, the U.S. Embassy said.

The Pakistani military launched their latest offensive against Taliban forces last month, after Swat militants pushed into adjacent Buner district, bringing them within 100 kilometres of the capital.

The army claims it has killed more than one-thousand militants and won back swaths of territory in Swat, a valley where the scenery and cooler climate once drew hordes of summer tourists.

But the army faces stiff resistance and has ventured no prediction of when the Taliban might be defeated.

Authorities say the clashes have prompted about 1.9 million people to flee their homes, creating a humanitarian crisis that could sap Pakistani enthusiasm for the effort if it drags on or is extended to other areas.

Relatives have taken in most of those driven out of Swat.

Officials have already declared some parts of Buner safe for refugees to return, despite continued clashes in the district.

However, Rear Admiral Michael A. LeFever, the top US military official at the American Embassy in Islamabad, forecast this week that between 200-thousand and 250-thousand will still be living in refugee camps at the end of the year.

Many thousands more are believed to be hunkered down in their homes, unwilling or unable to move.