Pakistan launched a “comprehensive operation” yesterday, sending troops, artillery and helicopter gunships against militants in the north Waziristan region, near the Afghan border.

The army announcement came after fighter jets had carried out air strikes against Taliban strongholds in the area, killing at least 50 militants, according to intelligence officials.

The air strikes came the day after millions of Afghans defied threats of violence by the Taliban to vote in the presidential run-off ballot to elect a successor to Hamid Karzai.

The raids, which a senior army official said resulted in a death toll that could “rise significantly”, followed an audacious terrorist attack a week ago on Pakistan’s busiest international airport in the southern port city of Karachi. This attack was linked to pro-Taliban Islamist militants from Uzbekistan.

In a statement yesterday the Pakistan army said: “There were confirmed reports of the presence of foreign and local terrorists in these hideouts [in north Waziristan] who were linked to the planning of the Karachi airport attack.

“Reportedly over 50 terrorists, mostly Uzbek foreigners, were killed. An ammunition dump has also been destroyed.”

Earlier in the week at least 25 Taliban were killed in bombing raids in another part of the border known as the Tirah valley.

Analysts said the attacks underlined the army’s growing determination to escalate the fight against militants, despite prime minister Nawaz Sharif’s government continuing to pursue a controversial peace process with the Taliban.

“It seems the military has decided that the negotiations with the Taliban will not yield any positive result,” said retired Maj Gen Mahmud Durrani, a former national security adviser to a Pakistani prime minister. “The attacks on Sunday are definitely a new phase in the war against the Taliban.”

Critics have questioned Mr Sharif’s reluctance to end negotiations, even as militants step up attacks.

“Nawaz Sharif is still being driven by political expediency,” said Imtiaz Gul, head of the Islamabad-based Centre for Research in Security Studies.

Mr Gul echoed a wider view that Mr Sharif is refusing to support an all-out war because of concerns over a militant backlash targeting Punjab, his home province.

– (Copyright The Financial Times Limited 2014)