Pakistan sent fresh troops to the volatile Swat valley on Friday after ordering the army to "eliminate" extremists battling government forces for control of the key northwest district.
Authorities slapped an indefinite curfew on a swathe of land to facilitate the deployment of troops, a senior military official told AFP.
The move came after attack helicopters, artillery and warplanes pounded suspected Taliban hideouts on Thursday in the deadliest fighting since the government reached a February peace agreement with hardliners.
In a televised address, Prime Minister Yousuf Raza Gilani called for unity against extremists he said were threatening the nation's sovereignty and who had violated the deal.
President Asif Ali Zardari, in Washington for talks aimed at quelling the chronic unrest gripping the nuclear-armed US ally, vowed military operations would last until "normalcy" had returned to Swat.
"It's a regional problem, it's a worldwide problem," he said after meeting key Congressional leaders considering a massive aid package for Islamabad.
"I think the world is coming to that realisation."
US President Barack Obama has placed Pakistan at the heart of the struggle against Al-Qaeda and is pressing Islamabad to crush the militants, branded by Washington as the biggest terror threat facing the West.
The deeply controversial February peace deal in Swat was designed to end a nearly two-year violent Taliban uprising by agreeing to place the region of some three million people under strict sharia law.
Critics charged it would merely embolden the Taliban, who advanced further south toward Islamabad, and amounted to little more than capitulation.
"An indefinite curfew was imposed early Friday, from Malakand district to Swat valley, in order to facilitate the deployment of troops," the military official told AFP.
He declined to say how many more troops were being deployed.
In his address, Gilani said the armed forces had been called "to eliminate the militants and terrorists" in order to restore the "honour and dignity of our homeland."
"The time has come when the entire nation should side with the government and the armed forces against those who want to make the entire country hostage and darken our future at gunpoint," he added.
He said militant efforts to disrupt peace and security had reached such a stage that the government believed "decisive steps" had to be taken.
The military said late Thursday that nine soldiers had died in the previous 24 hours in Swat, including seven in an ambush at Mingora, the main town.
Army chief General Ashfaq Kayani said he would deploy "requisite resources to ensure a decisive ascendancy over the militants."
The fighting is also imposing a huge burden on civilians, more than 40,000 of whom have fled Mingora, according to local officials.
The Red Cross warned Thursday that the crisis was escalating as thousands more bedraggled refugees streamed out of Swat, some on foot leading goats and cattle, others crammed into cars with bags, blankets and bundles of clothes.
Nasir Jamal, a medical shop owner, said a mortar hit the outer wall of his house.
"Luckily, we survived. I feel God has given me an opportunity I can't miss. I'm leaving. Swat is not worth living in," he said.
"Civilians are suffering at the hands of both the army and the Taliban. The Taliban are killing residents who don't side with them."
The government in North West Frontier Province said that more than 150,000 displaced people were living in temporary accommodation, although it did not say when or how long ago they had fled.
US Defence Secretary Robert Gates, speaking during a visit to Kabul, hailed Pakistan's action against the Taliban and voiced confidence that Islamabad's nuclear arsenal was secure.