They apparently hoped the two prisoners would be able to climb aboard a dangling ladder. An exchange of gunfire broke out during the attempt, with the helicopter's hijackers shooting and injuring a guard in a watchtower. The people aboard the helicopter dropped a bag containing weapons into the courtyard before flying off, police say. The two prisoners used the weapons to take the security guards hostage. An elite police force is continuing to negotiate for the release of the two guards still held captive.
Police say they are unharmed.
The helicopter's hijackers abandoned the aircraft at a nearby stadium. Investigators have spoken to the pilot, who has been released.