Pakistani officials say the spate of recent bloody attacks in Peshawar and surrounding areas, which have killed more than 150 people, were likely to have been co-ordinated from Barra.
Officials on Tuesday also imposed a curfew in Bajaur district, north of Khyber, after deadly clashes with the Taliban.
Authorities imposed an indefinite curfew after clashes in Khar, the main town of Bajaur district on the Afghan border, where US officials say al-Qaeda is plotting attacks on the West.
The unrest in Bajaur comes after a six-month operation the army said was a success [AFP]
"The crossfire continued for three hours. Six militants were killed in retaliatory fire," Adalat Khan, a local government official, told the AFP news agency.
"Two civilians were also killed and four, including two women, wounded when a mortar shell landed inside a house," Khan said.
Taliban fighters have recently stepped up attacks on security forces and government installations in Bajaur, one of Pakistan's seven semi-autonomous tribal districts.
The violence has surged since Pakistan launched a major offensive in the Taliban bastion of South Waziristan on October 17.
Officials say the aim is to distract the army's attention from South Waziristan.
The continued unrest comes despite a six-month operation in Bajaur, which the army declared a success in February.