Pakistani soldiers killed at least 12 militants during overnight gunbattles in three Taliban strongholds while militants hurled a grenade at a school in Quetta in the northwest, intelligence officials said yesterday.

"In last 24 hours, 12 terrorists have been killed, and five soldiers including two officers were injured," the statement said.

The officials, speaking on condition of anonymity because they are not authorised to speak with the media, said that while the Pakistan military has taken control of two of the strongholds Sararogha and Ladha there were still occasional clashes with militants. The army was still battling for full control of Makeen, which they call the "nerve centre" of the Pakistani Taliban.

In Quetta, two teachers and a student were injured Saturday when suspected militants hurled a hand grenade at a girls' school in insurgency-hit southwestern Pakistan, police said.

The militants lobbed the grenade at a state-run junior school in Quetta, the capital of oil- and gas-rich Baluchistan province, which borders Iran and Afghanistan, senior police officer Khalid Manzoor said.

The grenade blew off the staff room's roof and splinters hit two female teachers and an eight-year-old student, he said.

"The teachers had wounds to their heads but both are out of danger in the hospital," Manzoor said, adding that the student had only minor injuries.

No one claimed responsibility for the attack.

Grenade and bomb explosions and drive-by shootings are fairly frequent in impoverished Baluchistan province, which is gripped by an insurgency.

Earlier Taliban militants killed three Pakistani soldiers in an assault on a check post in the northwest as the military pressed its ground and air offensive, officials said Saturday.

The militants launched a rocket and gun attack on a paramilitary post in Torawari area of Hangu district late Friday, a security official said.

Three soldiers were killed in the raid, he said.

A senior police official said the attackers were Taliban militants who came from the neighbouring tribal region of Kurram.

Security forces based in a nearby fort responded by killing at least six attackers, police and military officials said.

The attack came as Pakistan's military continued a major ground and air offensive against Taliban strongholds in the lawless South Waziristan region near the Afghan border.

In mid-October, Pakistan launched an offensive in South Waziristan, a semiautonomous tribal region where Islamabad has seldom had significant influence, and which has become the main Taliban and al-Qaida sanctuary in the country. The military says hundreds of militants have been killed in the fighting a claim the Taliban dismisses.

The reality of the situation remains unclear. While refugees fleeing the area have reported fierce fighting, there have been next to no specific details. Journalists are not allowed into the region except on carefully orchestrated government trips.

The offensive has sparked a wave of retaliatory attacks across Pakistan.

Pakistan, vowing to crush Tehreek-e-Taliban in the region, has claimed a series of successes in its three-week old offensive, in which 446 Taliban fighters and 42 troops have been killed.

The casualty figures cannot be verified because communication lines are down and journalists and aid workers barred from the area.

South Waziristan is dubbed by Washington as the most dangerous place in the world because of an abundance of al-Qaeda and Taliban fighters.

The long-awaited assault on South Waziristan came after a spring offensive in the northwestern Swat valley. In July, the government declared the offensive a success but sporadic outbreaks of violence have continued in the valley.

Some 30,000 troops backed by fighter jets and helicopter gunships launched a fierce air and ground offensive into the northwest region three weeks ago and the military has since claimed a series of successes.