Berlin airport is battling to restore its check-in and baggage handling systems after a cyberattack at the weekend, with further delays and cancellations possible on Wednesday, the airport operator said in a statement.
Berlin is one of several airports across Europe impacted by the disruptions, attributed to a ransomware attack on software provider Collins Aerospace, which have affected dozens of flights and thousands of passengers since Friday.
It may take several more days before the German capital's airport has functional and secure software again, with staff working flat out to process passengers manually in the meantime, the BER operator said in a statement.
The software provider "has called in other experts and is working urgently to find a solution," it added.
Passengers should be prepared for long delays, and the airport encouraged people to check with their airlines in advance whether their flight was still planned.
Collins Aerospace said on Monday that it was working with the affected airports, which also include Brussels and London Heathrow, Europe's busiest.
Berlin airport was particularly busy after a marathon took place in the city over the weekend, with many runners struggling to return home.

Kenya offers temporary amnesty to undocumented East Africans amid crackdown fears
7 Indonesian airports remain shut due to volcanic ash from Anak Krakatau
Bolivia confirms 7 deaths after military base explosion
Israeli strikes on southern Lebanese town kill 11, state news agency saysÂ
Nepal marks national mourning day after deadly flood
Far-right AfD wins historic victory in German state election
At least 5 killed in Amazon Prime Air cargo plane crash in Miami
Israeli strike kills 2 in Gaza, medics say
