Helicopter gunships and artillery on Tuesday bombarded two militant hideouts that had been used to launch attacks on security forces in a troubled tribal region near the Afghan border, the Pakistani army said.

Spokesman Maj. Gen. Waheed Arshad said forces targeted a pair of compounds in Daygan, a village about 10 miles west of North Waziristan's main town of Miran Shah after receiving "credible intelligence that militants were present there."

It appeared to be the army's toughest military action in the lawless border region after a month of escalating violence, and came a day after foreign ministry spokeswoman Tasnim Aslam said Al Qaeda and the Taliban had no safe havens in the tribal zone.

Cobra helicopter gunships and artillery launched the attack early in the morning and it lasted about four hours, Arshad said. No ground forces were used in the assault, and there was no immediate word on militant casualties.

"The militants used to regroup and prepare attacks on security forces and take refuge at these compounds, so security forces targeted them," Arshad told Dawn television, calling the compounds a "staging post."

A local security official, speaking on condition of anonymity because he was not authorized to speak to journalists, said the militants had retaliated and both sides had used light and heavy weapons.

Residents in Miran Shah could hear the artillery and said a stray mortar struck a home, wounding three civilians, including two children, who had been transported to a hospital in the town.

The security official confirmed that some weapons fire had hit a home in Daygan, and that three or four people had been injured.

The assault appeared to be the toughest military action since troops that were withdrawn from key checkpoints under a controversial peace deal with pro-Taliban militants in September 2006 were redeployed to North Waziristan about a month ago — prompting militants to pull out of the deal and resume attacks.

President Gen. Pervez Musharraf, a key ally of the United States in its war on terror, is under pressure from Washington to crack down on militants after U.S. intelligence agencies concluded that the peace deal had allowed al-Qaida to regroup.

Musharraf said Tuesday that recent suggestions from the U.S. that it might launch unilateral strikes against Al Qaeda in Pakistan were "counterproductive" to the fight against terrorism, the government said.

Musharraf's comments were the highest-level rejection by Pakistan of comments by senior U.S. officials and presidential candidates about the possibility of U.S. strikes within the country, a possibility that Pakistan views as challenging its sovereignty.

President Bush said Monday that the U.S. and Pakistan, if armed with good intelligence, could track and kill Al Qaeda leaders in Pakistan, but stopped short of saying whether he would ask the Pakistani president before dispatching U.S. troops there.

Violence has surged in Pakistan, particularly along its northwestern frontier with Afghanistan, since an army raid on Islamabad's pro-Taliban Red Mosque in early July. In all, more than 350 people have died in suicide bombings and clashes between militants and security forces.

Pakistan says it has 90,000 troops deployed near the border to combat militancy and attacks on Western and Afghan forces in Afghanistan.

Meanwhile, A bomb exploded at a bus station in the northwestern Pakistan city of Peshawar on Tuesday, but no one was hurt, police said.

The explosion ripped through Peshawar's main terminal near an empty bus, said Fazl-e-Maula Khan, a city police officer.

Khan said no one was hurt in the blast.