LONDON — British authorities announced early Saturday that a man and a woman had been arrested in their investigation of unauthorized drone flights at Gatwick, the country's second busiest airport.

The arrests were made shortly after 10 p.m. local time (5 p.m. ET) on Friday in connection with "criminal drone activity," Sussex police said in a statement.

Police officers survey Gatwick Airport runways as flights resume on Dec. 21, 2018. Jack Taylor / Getty Images

The names of the suspects have not been released, but on Saturday police confirmed a 47-year-old man and 54-year-old woman were arrested in the town of Crawley, less than five miles south of the airport. They remain in custody, police said.

"Proactive investigations are still on-going," police said. "We urge the public to contact us if they believe they have information that can aid us further."

Gatwick is seeking to run a full schedule Saturday. In a statement, the airport said it is operational but urged passengers to check the status of their flights.

"Safety is Gatwick's top priority and we are grateful for passengers' continued patience as we work to get them to their final destination in time for Christmas," a Gatwick spokesman said.

Drones began buzzing the airport Thursday, leading to a 36-hour closure that affected more than 120,000 passengers during the height of holiday travel, officials said. A drone sighting Friday led to a second, brief shutdown of the airport.

"The military measures we have in place at the airport have provided us with reassurance necessary to re-open our airfield," airport officials tweeted.

Those measures include an Israeli-developed radar system that can track drones and jam their signals, England's Sky News reported.

Authorities were concerned the drones could disrupt airplane flight paths, disable jet engines or worse.

"We continue to urge the public, passengers and the wider community around Gatwick to be vigilant and support us by contacting us immediately if they believe they have any information that can help us in bringing those responsible to justice," Sussex police Superintendent James Collis said in a statement.

The identities of the suspects were not released.

The persistent drone crisis at Gatwick, which is located 30 miles south of London and serves 43 million passengers a year, has had ripple effects throughout the international air travel system.

Linda Givetash reported from London, and Dennis Romero from Los Angeles.