Islamabad. A motorbike bomb killed at least six people in an attack to a pro-government tribal elder’s vehicle in northwest Pakistan, police said.The attack took place on Monday in the town of Doaba in Khyber Pakhtunkhwa province, 190 kilometres west of the capital Islamabad and near the tribal belt where Taliban and other al-Qaeda-linked fighters have strongholds."A remote-controlled device planted on a motorbike parked on the roadside went off when a vehicle owned by Malik Habibullah, a local pro-government elder, passed by,” local police chief Sajjad Khan told AFP.It was not immediately clear whether the elder, Malik Habibullah Khan, was among the dead, but his vehicle was damaged in the blast.The blast also damaged several nearby vehicles and shops. No one has claimed responsibility for the attack.Elsewhere in the northwest, two policemen were killed while defusing a bomb in the district of Swabi, 50 kilometres northwest of Islamabad, police said."The two policemen had already defused four bombs planted near a government boys’ school in the area but a fifth bomb exploded while being defused, killing both of them,” local police chief Mian Muhammad Saeed said.Pakistani troops have for years been locked in deadly battles with domestic fighters in parts of the northwest.The Pakistani government has encouraged tribesmen in the northwest to form fighters to fight against the Taliban. The fighters have carried out many retaliatory attacks against the group.The US has in the past accused Pakistan of not doing enough to crack down on Taliban fighters who also plot attacks on Western targets and in neighbouring Afghanistan.