MINGORA, Pakistan - The military offensive to expel the Taliban from Pakistan's Swat Valley could take another two months to complete, and troops may have to stay for a year to prevent militants from retaking control, commanders said yesterday.

The armed forces have secured control over several key towns during the month-old campaign in the northwestern region, but the fighting has uprooted three million people and triggered suspected reprisal attacks elsewhere in the country.

The chief army spokesman, Maj. Gen. Athar Abbas, told reporters on a military-organized tour of the town of Mingora that by "a rough estimate" it could take an additional two months of fighting to uproot the militants from their hideouts in the lush valleys of Swat and surrounding areas.

Earlier, Maj. Gen. Ijaz Awan, a senior commander in the eight-day battle for Mingora, said the military was gearing up for a fight in the nearby town of Kabal, where top Taliban leaders are suspected of being holed up.

"We have bottled them up very well," Awan said. "Hopefully this will be a decisive battle here" in Kabal. "Their deaths are vital to killing their myth."

The battle for Swat, launched in late April after the militants abandoned a peace deal that gave them control of the northwestern region bordering Afghanistan, is seen by Washington as a test of Pakistan's resolve against extremists.

The United States strongly backs the campaign, and it has enjoyed broad support among Pakistanis. But that support may sour if civilian casualties turn out to be high or if the government appears to bungle the refugee crisis.

The government must also contend with attacks elsewhere that officials say are an attempt to distract the military's attention from Swat.

One such attack was Monday night's ambush-kidnapping of scores of students from a military cadet school in North Waziristan, near the Afghan border.

Richard Holbrooke, the U.S. special envoy to Afghanistan and Pakistan, held talks in Islamabad yesterday with President Asif Ali Zardari and was to visit a refugee camp today.

Holbrooke rejected as "ludicrous" a claim by Osama bin Laden in a new recording that the United States was responsible for the Swat refugee crisis because it pressured Pakistan into carrying out the offensive.

He also announced that President Obama had asked Congress to approve $200 million more in aid for the refugees, on top of $110 million already pledged.

He said rebuilding towns and resettling refugees would be critical for Pakistan's government. Power, water, and gas remain cut in Mingora, the largest town in Swat, and food is short. Officials are discouraging refugees from returning home yet.

During yesterday's military tour through parts of Mingora, an AP reporter saw soldiers but little sign of the 40,000 residents still there.

At a crossroads dubbed the "bloody intersection" by locals because the Taliban would leave mutilated bodies there as a warning, there were signs of battle. Chunks of a multistory building were blown away, and security gates were torn off at least one storefront. Broken glass and bricks lay all around.

Awan said that the military hoped about 2,500 police would return to Mingora by June's end but that the army would probably have to stay in the Swat region for at least one more year to secure it.