Certain areas of Amsterdam’s Schiphol airport have been closed after a suspected World War II bomb was discovered, a spokeswoman said.
The departure hall serving most European destinations has been evacuated as a precautionary measure.
Delays are now affecting some departures and passengers are advised to check their flights before leaving for the airport.
A bomb disposal team is trying to establish whether the device is live.
Certain areas of Amsterdam's Schiphol airport have been closed after a suspected World War II bomb was discovered
The bomb was uncovered by workers digging near Pier C, which connects the main plaza with Departure Hall One, serving most destinations within Europe’s 26-country passport-free Schengen zone.
“This will have a big impact. We can park planes somewhere else to some extent but at some point it will lead to cancellations or delays,” the spokeswoman said earlier, according to Reuters news agency.
Schiphol was used as a military airfield by Nazi Germany during the 1939-45 war, and was often attacked by allied bombers, Dutch media said.
It is now one of Europe’s busiest airports, handling some 48 million passengers every year.
Unexploded bombs dating back to the war are still frequently discovered in Europe.
A 550 lb (250 kg) American bomb was detonated by a bomb disposal team in the German city of Munich on Tuesday.
A 1.5-tonne mortar bomb probably fired by Nazi forces was also safely removed from the Polish capital, Warsaw.
Amsterdam’s Schiphol airport has been evacuated after Dutch police has arrested a man who locked himself in a toilet and claimed to have a bomb.
Schiphol’s two main international terminals were evacuated at about 11:30, as the bomb squad and scores of police arrived at the scene.
The terminals reopened about four hours later, after officers said the man posed no threat to the public.
However, delays continued to affect the airport – one of Europe’s busiest.
Dutch border police were investigating whether the suspect had explosives in his luggage.
Live television streams had shown police with guns, dogs and balaclavas outside the building, she added.
Amsterdam's Schiphol airport has been evacuated after Dutch police has arrested a man who locked himself in a toilet and claimed to have a bomb
By 16:00 local time, Schiphol’s website was showing 16 cancellations to inbound flights and 11 to departures. Dozens of flights were delayed.
A Schiphol spokesman said: “Things are not back to normal yet. The evacuation is over and we are busy getting operations back on track but there will be some delays and cancellations for the rest of the day.”
On 25 December 2009, a Nigerian student smuggled explosives on to a flight from Schiphol to Detroit in the US after flying into Amsterdam from Lagos.
He has pleaded guilty to trying to blow up the Northwest Airlines jet he boarded and is due to be sentenced on Thursday. He faces life imprisonment.