KABUL - A Taliban fighter driving a Humvee packed with explosives blew himself up outside a police headquarters in the northern Afghan city of Pul-e-Khumri and other fighters opened fire on security forces there, the Taliban said in a statement on Sunday. 'Several other Taliban fighters are presently clashing with the Afghan forces,' spokesman Zabihullah Mujahid said. Government officials in Baghlan province confirmed the explosion in the provincial capital.