With less than 24 hours to go until North Korea's Kim Jong Un meets U.S. President Donald Trump, security is tight in and around the temporary residences of the two leaders.Kim Jong Un and Donald Trump are, respectively, staying the St. Regis and Shangri-la hotels in central Singapore.Visits to both on Monday saw NK News encounter police road blocks and strict prohibitions about when - and where - photography was permitted.Cars were restricted from entering areas in the vicinity of the temporary residences of the two leaders, while those on foot were permitted to walk down streets