Pakistani security officials check motorcylists at a road-side checkpoint in Peshawar, the provincial capital of Khyber-Pakhtunkhwa province. Security has been intensified across the country.

AFP

The Pakistani Taliban yesterday warned foreign firms to leave the country and vowed to hit back against the government after tanks, troops and jets were deployed in a long-awaited offensive on their stronghold.

Pakistan's major cities braced for revenge attacks by tightening security at key installations and ordering soldiers to patrol the streets, while hospitals in the northwest prepared for casualties. 

The offensive in North Waziristan, the main bastion of Taliban and Al-Qaeda militants, was launched a week after a brazen insurgent attack on the country's main airport in Karachi left dozens dead and marked the end of a troubled peace process.

Pakistan's allies, particular the United States, have called for an operation in the mountainous tribal territory to flush out groups like the Haqqani network, which use the area to target NATO troops in neighbouring Afghanistan.

But authorities had held back from a final push -- possibly fearful of angering warlords who attack only Afghanistan and of opening too many fronts in their decade-long battle against homegrown Islamist insurgents.

 The Tehreek-e-Taliban Pakistan (TTP) warned foreign countries to stop doing business with the government and supporting its "apostate army". 

"We warn all foreign investors, airlines and multinational corporations that they should immediately suspend their ongoing matters with Pakistan and prepare to leave Pakistan, otherwise they will be responsible for their own loss," main TTP spokesman Shahidullah Shahid said in a statement.

"We hold Nawaz Sharif's government and the Punjabi establishment responsible for the loss of tribal Muslims' life and property as a result of this operation," he added, vowing to "burn your palaces" in Islamabad and Lahore.

Large numbers of troops were seen patrolling the streets of Islamabad, Lahore and Karachi.

In the northwestern Khyber-Pakhtunkhwa province which borders the tribal zone, the government has declared a state of emergency in all hospitals and told them to prepare for casualties, provincial health minister Shahram Khan Tarakai said.

Air force jets have been pounding suspected militant hideouts in the region since Sunday and have been joined by tanks and infantry engaging in heavy artillery strikes.

The military yesterday sustained its first casualties, losing six soldiers to a bomb blast at the village of Ghulam Khan, according to an official statement. Three others were injured.

An AFP reporter in North Waziristan's main town of Miranshah said tanks were now stationed in the bazaar. Troops were firing intermittently in the air to warn people not to leave their homes but so far there had been no reports of close combat.

More than 2,000 soldiers could be seen at new posts set up in the mountains. Pakistan already had troops stationed in the tribal district, but these were reinforced in the days leading up to the offensive.

The militants' death toll so far stands at 177, according to the military.

In the town of Bannu, 10 kilometres from the border with North Waziristan, hundreds of military trucks with roof-mounted machine guns were on their way to the combat zone, as were oil tankers and a military field hospital.