Chinese airport security, which often seems more logical than its American counterpart, looked a lot more like that of the United States on Monday.

Official media reported that fights broke out between angry passengers in long, impatient security lines at the Beijing airport, as passengers were delayed and caught off-guard by new, increased security measures. Would-be flyers were required to remove their shoes and belts, not usually needed before getting on a plane in China. Checks took far longer than usual. Because passengers weren’t notified in advance of the more rigorous screenings, several people reporting missing their flights.

Some reports say authorities have upped security measures over terrorist threats, but officials have not confirmed the reason.