Pakistani authorities on Sunday temporarily suspended a curfew in northwestern Swat Valley, to allow tens of thousands of civilians to flee the region where government troops are fighting Taliban militants.
The Associated Press reports desperate Swat residents were seen trying to leave the region any way they could - by car, animal-pulled carts and on foot - after the curfew was lifted for nine hours.
The U.N. refugee agency expects 500,000 people to flee the fighting, with many heading for displaced persons' camps.
The Pakistani military says it had killed about 400 insurgents since Friday in Swat and the neighboring Shangla district. Two soldiers also died in the latest fighting. There has been no independent confirmation of the casualties.
Pakistani troops backed by fighter jets and helicopter gunships launched a full-scale offensive in Swat and surrounding districts on Thursday after militants took control of other areas, some only 100 kilometers from the capital, Islamabad.
The international aid group World Vision says conditions in hastily-constructed displaced persons' camps are "intolerable" because of high temperatures, insufficient sanitary facilities and a lack of electricity.
A World Vision official said Sunday relief workers may not be able to meet the basic needs of refugees if they continue arriving at the camps at such a quick pace.
Pakistani officials say the Taliban violated a February peace deal that required them to disarm in exchange for the establishment of Islamic law (Sharia) in Malakand Division. The officials also accused militants of trying to set up a parallel government in the area. The Taliban blames the government for attacking militants.
An army spokesman said Friday the military was battling at least 4,000 militants in Swat Valley, including Uzbeks and Tajiks.
Some 15,000 Pakistani security forces are deployed in the region.
Some information for this report was provided by AFP, AP and Reuters.