Security stepped up as world leaders gather for UN General Assembly

Deep below the United Nations headquarters in Manhattan, where more than 140 world leaders are set to gather for next week’s General Assembly, the people charged with keeping them safe are preparing for what they call a National Special Security Event.

In the “brain center” a wall of monitors lights up the room showing dozens of the compound’s 1,400 live security camera feeds, door alarms and emergency alerts. Computers are…