WANA/Rawalpindi - Army soldiers began preparations on Friday for an offensive to try to push the Taliban from their last major stronghold in mountainous North Waziristan Agency.

The heavily forested ravines of the Shawal Valley are dotted with Taliban hideouts and the area is a key smuggling route into neighbouring Afghanistan.

"It is a massive military action against the Taliban militants and their allies in the Shawal mountains," said a government official who asked for anonymity because he was not authorised to speak about military operations.

The Taliban controlled almost all of the northwestern region of North Waziristan until troops launched an offensive there last year. The Taliban still control the Shawal Valley and have used it as a launchpad for attacks on forces.

The area is a stronghold of Khan "Sajna" Said, a leader of a Taliban faction whose name was added to a sanctions list of "specially designated global terrorists" by US authorities last year.

Air force jets began bombing the valley in the early hours of Friday, and a military statement said 15 militants were killed. A Taliban spokesman said the 15 were all civilians.

It was impossible to verify the reports because the fighting is in areas sealed off to journalists.

"Hundreds of trucks and pickups full of soldiers and weapons ... are moving towards Shawal," said Zainullah, a telephone operator in the valley.

"There are roadblocks everywhere, no one can come in or go out. There is a complete curfew and phones lines are also being cut." Several military officials told Reuters the military had requested help from Afghanistan to prevent militants from fleeing over the border.

Any cooperation would be a significant step forward in a thaw in relations that began when Afghan President Ashraf Ghani took office last year.

Neither the Pakistani nor the Afghan military responded to requests for comment. Government officials in the area said they were not authorised to comment.

A resident said there had been fighting between the militants and the military on the edge of the Shawal Valley and civilians feared being trapped.

"We are in fear, especially the kids," he said. "We are now preparing to leave the area and shift to safe places, because last night artillery shells were fired continuously."

According to AFP, air strikes on Friday killed at least 17 militants in the country's restive tribal areas bordering Afghanistan, security officials said, part of a major operation against the Taliban.

The strikes came two days after the massacre of 45 Ismailis in Karachi claimed by the Islamic State group (IS) and the Taliban's Jundullah faction which has previously reportedly allied itself to IS.

"The air force jets pounded the areas close to the Afghan border in thick forests. Three compounds and five vehicles were also destroyed in the action," a security official in Miranshah told AFP.

Two local residents confirmed the attack to AFP.

ISPR in a statement in Rawalpindi confirmed 15 terrorists were killed in precise aerial strikes near Datta Khel.

It said the terrorists who were killed included some foreigners as well.

The Air Force jets targeted militants' hideouts on the edge of the Afghan border in the thick mountainous forests in Wareka Mandi area of Shawal Valley in North Waziristan tribal region, 65 kilometres west of NWA capital Miranshah.

The official said that the killed militants included Uzbek and Afghan nationals and members of the Tehreek-i-Taliban Pakistan.

According to a private TV channel, air force jets targeted militants’ hideouts in Wareka Mandi area of Shawal and Dattakhel districts.

“The air force jets pounded the areas close to the Afghan border in thick forests and killed at least 32 militants. Three compounds and five vehicles were also destroyed in the action,” a security official in Miranshah said.

Meanwhile, Air Chief Marshal Sohail Aman, Chief of the Air Staff, Pakistan Air Force visited a Forward Operating Base of Pakistan Air Force in the Northern Areas.

The air chief visited the base and observed the operational readiness of PAF personnel. While interacting with the PAF personnel, he appreciated their level of motivation and dedication to duty.

He also highlighted the importance of comradeship among the personnel and reiterated that wonders could be achieved with sincere efforts and teamwork.