Pakistan Army has launched a major operation in its volatile tribal areas to stop the Islamic State making inroads into areas bordering Afghanistan, the military's spokesman said on Sunday.
Military spokesman Lieutenant General Asif Ghafoor said Islamic State - also known as Daesh - was growing in strength inside Afghanistan, prompting Pakistan to launch an operation in Federally Administered Tribal Areas (Fata).
"This operation was necessary because Daesh is getting established there and we have to stop the influence of Daesh spreading into Pakistani territory through the Rajgal valley," Ghafoor said, referring to a valley surrounded by mountains reaching up to 14,000 feet.
He said that the "Khyber 4" operation, which would include the Pakistan Air Force, would focus on the border areas inside the Khyber Agency area, which is part of Fata.
Ghafoor said across the Khyber border there are safe havens for multiple "terrorist" organisations that are linked to recent attacks in Pakistan, including the Parachinar assault.
Northwestern Pakistan's ethnic Pashtun lands are awash with weapons and the area remains the most volatile region in the country despite the military's success in driving out many Al-Qaeda and Pakistani Taliban militants.
Fighting has subsided in Fata in recent years and many internally displaced people have been sent back to villages reduced to rubble due to military operations against the Islamists over the past 15 years.
"Once this operation is completed, we will first secure the international border on our side and eliminate the hideouts of various terrorist groups," Ghafoor added.
Islamic State has had more success in neighbouring Afghanistan, where it controls small chunks of land, but has also faced tough resistance from the US-backed government in Kabul and local Afghan Taliban militants.
Pakistan is seeking support from Afghanistan to control the border but Ghafoor made it clear that it will not allow "foreign boots on the ground" in its territory.
Pakistan's military began building a fence along the 2,611 kilometre border with Afghanistan in May as part of its security programme.