The Pakistani Taliban have vowed to resist until the "last breath" as security forces entered two militant-held towns and fought on the outskirts of a third in what could turn into bloody urban battles near the Afghan border.

Taliban spokesman Muslim Khan made the defiant statements late Sunday after a top official said the military offensive in the Swat Valley and surrounding areas had killed more than 1,000 suspected militants and would proceed until the last insurgent is "flushed out."

"We will fight until the last breath for the enforcement of Islamic law," Khan told The Associated Press in a brief phone call from an undisclosed location. "We consider ourselves on the right path."

Washington has pressed Islamabad to crack down on Al Qaeda and Taliban strongholds along the Afghan frontier, saying the militants threaten not only U.S. and NATO troops in Afghanistan but also nuclear-armed Pakistan's future.

Swat was once a tourist destination that fell prey to Taliban advances over the past two years. The military's latest offensive in Swat and neighboring districts has already led to an exodus of nearly 1 million people. About 100,000 of them are now in sweltering refugee camps.

The battle in Swat's towns in particular could prove a stiff test for Pakistan's military.

The army is geared toward fighting a conventional battle against longtime rival India on the plains of the Punjab region using tanks and artillery, and it has limited experience battling guerrillas in urban settings.

The military has tried operations in Swat before but failed to force out the Taliban, many of whom could blend in easily with the regular population or had hideouts in the mountains. Civilians in Swat said the military's heavy use of airstrikes killed many innocents instead of militants.

In a statement Sunday afternoon, the army said 25 militants and a soldier died in the previous 24 hours of the operation.

Security forces engaged in firefights with militants on the outskirts of Swat's main town, Mingora, where many of the estimated 4,000 Taliban fighters in the valley are believed to be holed up, the statement said.

It also said security forces had surrounded and entered the towns of Matta and Kanju to take on the militants, and it requested civilians still in those areas stay away from the Taliban hide-outs.

Troops were making gains in the remote Piochar area, the rear base of Swat Taliban leader Maulana Fazlullah, it added.

Army spokesmen reached Monday morning said they had no new updates.

In giving the 1,000-plus death toll Sunday, Interior Minister Rehman Malik said the operation was going well and would "continue till the last Taliban are flushed out."

It was not possible to independently verify the death toll.

The territories bombarded over the past three weeks are now too dangerous for journalists to freely roam. The army also hasn't explained how it is differentiating militant deaths from civilian ones. It hasn't given a civilian death toll. Accounts from witnesses and doctors suggest dozens of civilians have been killed or wounded.

"The operation is going in the right direction as we had planned," Malik said. "I cannot give a time but we will try (to complete the operation) at the earliest."

The military also did not detail how many ground troops were involved in the latest advances.