(CNN) -- A suicide bomber blew himself up near a military convoy in northwest Pakistan on Thursday, killing five people and injuring more than 40, a local government official said.
The fatalities included two women, authorities said. The blast near a bus station targeted the convoy driving through Mingora, Imran Qureshi told reporters.
Qureshi said the nature of the explosion was not known. It was unclear whether any of the victims are soldiers.
Video on local TV showed charred remains of vehicles as soldiers inspected the scene.
Last year, the Pakistani army launched a major offensive against the Taliban in the Swat Valley, and military officials say the region has been cleared of extremists.
Militant attacks have decreased significantly in the area this year. The last one in March was a suicide attack that killed more than a dozen people just outside Mingora.
Mingora is the largest city in Pakistan's Swat Valley.
Journalist Nasir Dawar contributed to this report