A suicide bombing and a roadside bomb blast on Friday killed at least four government troops and injured nine in Pakistan's north-west tribal belt by the border with Afghanistan, DPA reported. A suspected Islamic militant rammed an explosive-packed car into an army convoy travelling near Miranshah in North Waziristan, killing himself and four soldiers and injuring more than six, a military official said on condition of anonymity. The casualty numbers were expected to rise, he said. In a separate incident in the same area, three members of the paramilitary Frontier Corps were injured when an explosive device detonated by their vehicle during a water delivery, an army spokesman said. A day earlier, five people were injured in Miranshah when militants fired rockets and light artillery at a checkpoint, damaging a nearby hospital in the process. North Waziristan and the border regions as a whole have seen a sharp rise in attacks on security forces since the government sent troops to storm a radical mosque in the capital Islamabad in July. Local tribes responded by scrapping peace treaties with the government, which is under mounting US pressure to eradicate Taliban and al-Qaeda elements in the mountainous region.