Militants attacked a military base near the Afghan border Thursday, sparking a battle which drew in army helicopters and left up to 30 insurgents died, the army said.

Military spokesman Maj. Gen. Waheed Arshad said nine soldiers were wounded in the fighting near Razmak, a town in the South Waziristan region where pro-Taliban militants hold sway. The clash occurred a day after a top visiting U.S. official praised Pakistan's efforts against militants.

"There were repeated attacks, which were repelled. Nine of our soldiers were injured, and we are hearing from local sources that militants suffered massive casualties," Arshad told The Associated Press.

He said between 25 and 30 militants were killed, but denied reports from three intelligence officials who said 10 soldiers were killed. The officials spoke on condition of anonymity because they were not authorized to speak publicly.

One of the intelligence officials told the AP that another four to six soldiers were missing after the attack on the Nawaz Fort base. He said helicopter gunships had joined the battle, which began at 1 a.m. and was continuing late Thursday morning.

Fighting between Islamic militants and security forces has been raging across northwest Pakistan since the army assailed a radical mosque in the capital, Islamabad, in July. Most of the combat has taken place in the rugged mountains along the Afghan frontier, where Taliban and al-Qaida militants appear to be gaining strength.

On Wednesday, the army said it had killed about 40 militants in the North Waziristan region.

Pakistan also has witnessed several suicide attacks in otherwise peaceful areas, including two blasts on Sept. 4 that killed 25 people and wounded more than 60 in Rawalpindi, where the army has its headquarters.

U.S. officials have welcomed signs that Pakistani President Gen. Pervez Musharraf, who is currently seeking a new five-year term, is taking a tougher line.

"There is no doubt whatsoever of Pakistan's commitment to restoring and establishing security in that part of the country and more than doing its share in the war against terror," visiting U.S. Deputy Secretary of State John Negroponte said Wednesday.

The army says it has deployed 90,000 troops in the border region in an attempt to curtail militancy and stop guerrillas from crossing into Afghanistan to attack NATO forces.

But the military had scaled back its operations under disputed peace deals signed last year, and there is growing alarm that extremists have used the breathing space to exert control over ever-greater areas of North West Frontier Province.

Militants are currently holding hostage some 260 soldiers seized in South Waziristan on Aug. 30 and are waging a morality campaign reminiscent of the former ruling Taliban regime in Afghanistan.

Extremists are pressuring shopkeepers in the region not to sell music or movies and barbers not to trim beards or face punishment for encouraging behavior they consider un-Islamic.

In the latest incident, a bomb planted in a market near the city of Kohat destroyed six stores selling music CDs, two tailor shops and one barber shop before dawn on Thursday, local police officer Anwar Khan said. No one was reported hurt.