Nineteen domestic airports have beefed up security for the Olympics. They include Beijing's Capital International Airport, those in Olympic co-host cities, Xinjiang Uygur Autonomous Region and Tibet Autonomous Region.

All passengers and their carry-on luggage now have to be checked for explosives at all terminal entrances. Airport staff and even people just picking up or seeing off passengers must also be checked before entering the terminals.

Anyone refusing to be checked or found with explosives will face punishment according to the law.