Thousands of people have poured into the refugee camps
Nearly 1.5 million people have been displaced by this month's fighting in north-western Pakistan, the United Nations refugee agency says.
The Pakistani military has been engaged in major operations against the Taleban in the area.
The UNHCR is calling for urgent and massive international help.
It says the 1.45 million displaced since 2 May is in addition to those displaced by fighting last year - bring the total to more than two million.
Thousands of people have streamed into camps seeking refuge from the conflict.
The speed with which people have fled their homes has taken experienced UN aid workers by surprise.
They say some parts of the Swat valley have been emptied of their populations.
The UNHCR says the crisis could destabilise the entire region unless there is a massive response from the international community.
Pakistan's Prime Minister, Yousuf Raza Gilani, has described the situation as the country's worst refugee crisis since the partition of India and Pakistan in 1947.