Passengers were evacuated from a terminal in London's Gatwick Airport on Saturday morning in response to an apparent security alert.
Local police said that bomb disposal experts were called shortly after 9.30 a.m., local time after a man was seen acting suspiciously inside the airport's North Terminal.
The man was arrested and the suspicious package was investigated.
A statement from Sussex Police, the local police force, said that they were called "following suspicious actions by a man who discarded an item at the airport".
It added: "The man was arrested and EOD [explosive ordinance device] specialists have been called to the airport to investigate the item".
Detective Superintendent Nick May said that there was heightened awareness following Friday's attacks in Paris.
"At this time, we are investigating the circumstances of the incident and it is too early to say what the item may be. However, given the events in Paris on Friday evening, there is heightened awareness around any such incident and it is best that we treat the matter in all seriousness," May said.
"We are aware that there is concern about what has happened in France, but the general threat level remains the same and people should be aware as usual of anyone acting suspiciously," he said.
Travellers at the airport posted images on social media of passengers standing outside the terminal building next to their luggage, waiting to be let inside.
University of London geography professor Tim Unwin, who appeared to be at the airport, wrote on Twitter that passengers were told to leave the North Terminal's first floor shortly after 10 a.m., local time.
Flights appeared to still be taking off, but with shorts delays, according to the airport's website.
Gatwick, 45 kilometers to the south of London, is the U.K. capital's second-largest airport.
Britain has not raised its terror threat level in response to Friday night's attacks in Paris, but police have announced increased patrols in crowded central London areas this weekend.