LAHORE, Pakistan (AP) — Black-clad Pakistani commandos overpowered a group of militants who had seized a police academy, took cadets hostage and killed at least six of them Monday in a dramatic challenge to the civilian government that faces U.S. pressure to defeat Islamic extremists. The security forces stormed the compound on the outskirts of Lahore to end the eight-hour siege by the grenade-throwing gunmen, with three militants blowing themselves up and authorities arresting four, officials said.