Some departing flights from airports across Britain were disrupted on Tuesday after air traffic control provider NATS hit a technical issue, Heathrow Airport said, adding that arriving flights were not affected for now.

More than 600 flights were canceled on Tuesday due to a technical issue in Britain's air traffic control system, the flight monitoring website Flightradar24 reported.

"The air traffic control service NATS is experiencing a technical issue which is impacting departing flights at UK airports," Heathrow said in a statement. "Arriving flights are not currently impacted."

The disruption widened through the day, with Gatwick, Manchester and Stansted airports also reporting they were affected by the air traffic control technical issue, in addition to Heathrow.

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The airport said it was supporting the local NATS team in efforts to resolve the problem as quickly as possible and would share updates as they came in.

About 425 flights to and from U.K. airports, including Heathrow, were canceled, affecting services operated by multiple airlines, including British Airways, EasyJet, KLM and Lufthansa.

"We apologise to those disrupted and advise passengers to check with their airline for latest flight information," it added.

NATS handles air traffic across UK airspace and at several of the country's major airports.

Budget airline EasyJet said some of its flights were “unable to operate” and that the system failure caused “delays to flights across Europe.”