European airport operators and airlines sought to maintain business as usual following Friday’s terrorist attacks in Paris that killed at least 120 people and led the French government to impose a state of emergency.

Airlines including EasyJet Plc, Air France and British Airways offered passengers traveling to and from the French capital this weekend the option of delaying their journeys free of charge. Aeroports de Paris, which owns Charles de Gaulle airport, warned that inbound passengers may face customs and immigration delays of up to 40 minutes at two of the airport’s three terminals.

France has mobilized its military and shuttered cultural and tourist sites in the wake of what French President Francois Hollande has described as “an act of war” by Islamic State. The attack comes 11 months after extremists targeted the offices of the satirical French magazine Charlie Hebdo and amid growing evidence that a bomb downed a St. Petersburg-bound plane two weeks ago killing all 224 people aboard.

Gatwick Closed

The north terminal at London’s Gatwick Airport was evacuated earlier today after a man acting suspiciously left an item in the building. The man has been arrested and specialists are investigating, Gatwick said in a statement.

“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,” said Detective Superintendent Nick May.

London’s Metropolitan Police will be assessing events in Paris and is looking to beef up security across the U.K., assistant commissioner Mark Rowley said on the BBC.

“People may notice a little change at ports,” Rowley said, and “at events in big cities across the country: extra police officers, extra checks, extra vigilance.”

London’s Heathrow Airport, Europe’s busiest hub, said it was operating as usual. Eurostar, which runs rail service from the British capital to Paris and Brussels, said its trains were on time and also offered customers traveling today the option of changing their bookings to a later date.

Separately, EasyJet said it will operate six more evacuation flights from the Egyptian resort town of Sharm el Sheikh, the starting point of the crashed Russian Metrojet flight. After the U.K. government imposed a ban on flights between Britain and Sharm el Sheikh earlier this month, EasyJet, Thomas Cook and Monarch were among the airlines that canceled commercial flights.

This article was written by Kari Lundgren from Bloomberg and was legally licensed through the NewsCred publisher network.

Photo Credit: French police officers patrol at the France Italy border in Menton, southeastern France, Saturday, Lionel Cironneau / Associated Press