Police shot a gunman and safely freed the three people he had taken hostage in a four-hour standoff at the Discovery Channel headquarters outside Washington,police said. "Approximately 10 minutes ago the suspect was shot by police officers," Montgomery County police chief J Thomas Manger told reporters,adding that the gunman's condition was unknown but that he was "in custody." "All the hostages are safe and are out of the building," he said. Police had feared for the safety of the hostages,after more than two hours of negotiations between the gunman and authorities,he said. The gunman,an Asian male,had "what we believe to be explosive devices strapped to his front and back," Manger said,adding that the device "appeared to go off" but stressing that police were just beginning their sweep of the building to assess the situation.