At least two security personnel have been killed and seven others wounded after Pakistani Taliban fighters launched two separate attacks on security checkpoints in northwest Pakistan, officials say.
In Wednesday's first attack, a suicide bomber drove his explosives-filled car into a security checkpoint as fighters armed with guns stormed a nearby building in Shawa area of North Waziristan tribal district, killing two personnel, officials said.
The post is run jointly by the paramilitary Frontier Corps and tribal police and the adjacent building houses more than 40 security forces.
The umbrella Tehreek-e-Taliban Pakistan faction and al-Qaeda-linked fighters has led a bloody campaign against the Pakistani state in recent years, carrying out hundreds of attacks on security forces and government targets, concentrated largely in the northwest.
A local security official in Miranshah, the main town of North Waziristan tribal district and a hub of Taliban and al-Qaeda linked fighters, told AFP that the injured have been flown to nearby military hospitals.
Abu Baseer, a purported spokesman of little-known Taliban faction Ansarul Mujahideen, claimed responsibility for the attack.
He told AFP by telephone from an undisclosed location that the attack was in revenge for the death of Pakistani Taliban leader Hakimullah Mehsud, who was killed in a US drone strike in early November.
In a second attack in Swabi district, about 50km northwest of Islamabad, around a dozen fighters launched an attack at a police checkpoint before dawn on Wednesday, police said.
"The attack was successfully thwarted and four fighters were killed in the retaliatory fire by police," Sajjad Khan, district police chief, told AFP.
Elsewhere in Pakistan, in a separate incident on Tuesday, a Shia Muslim university professor and his driver were killed in an apparent sectarian attack in Punjab province.
Syed Shabbir Hussain Shah, the director of student services at the University of Gujrat, was on his way to work when armed men on a motorcycle sprayed his car with bullets and sped off.
"He had barely turned the corner of his house when he was attacked," Amir Malik, a policeman, said.
"By the time the ambulance arrived, he and his driver were both dead."
The police officer confirmed that Shah belonged to the Shia sect that makes up a fifth of Pakistan's population and
has suffered a rising number of attacks in recent years.
Most of the attacks are the work of Sunni Muslim activists affiliated with banned groups such as the Taliban or
Lashkar-e-Jhangvi, which wants to drive all Shia Muslims out of Pakistan.
More than 800 Shia Muslims have been killed in targeted attacks in Pakistan since 2012, including about 400 this year, figures released by the Human Rights Watch organisation in November show.