DERA ISMAIL KHAN/WANA, Pakistan (Reuters) - Pakistani troops began preparations on Friday for an offensive to try to push the Taliban from their last major stronghold in mountainous North Waziristan.
The heavily forested ravines of the Shawal Valley are dotted with Taliban hideouts and the area is a key smuggling route into neighboring 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 authorized to speak about military operations.
The Pakistani 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 Pakistani 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 U.S. authorities last year.
Pakistani 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.
"Jets bombed the houses of innocent people, none of our men or mujahids were killed in these air strikes," he said.
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 Pakistani 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.
NATO forces, which left Afghanistan last year, had repeatedly urged Pakistan to take action against Taliban havens.
Neither the Pakistani nor the Afghan military responded to requests for comment. Government officials in the area said they were not authorized 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."
Additional reporting by Haji Mujtaba in Banni and Javed Hussain in Parachinar; Writing by Katharine Houreld; Editing by Andrew Roche