A light aircraft, hijacked by a pilot who threatened to crash it into New Zealand's highest building in Auckland, has plunged into the city's harbour. Radio New Zealand said the 328m Sky Tower was evacuated on Saturday after threats were made by the pilot, who said the plane had been stolen from a local airport south of Auckland. The tower sits on top of a large casino and hotel complex in the centre of Auckland, New Zealand's biggest city. It was not immediately clear how many people were aboard the plane and what their condition was. Police boats were moving towards the spot where the plane went down. Police were unavailable for comment and there were no further details.