Somali suspects arrested on Christmas Eve were believed to be planning to shoot down an military helicopter, according to a report in the Dutch daily De Telegraaf on Tuesday.
The paper cited a "reliable source" in the secret service, the AIVD, who said that the suspects were targeting the major Dutch military airbase of Gilze-Rijen, in the south of the country, DPA reported.
The report claimed the men were planning to use a portable rocket launcher, which was to be imported from Belgium, Denmark or another European country.
"Simply put: the only thing they were missing was the equipment to shoot something down," the security source told the paper.
There are 85 helicopters stationed at the Gilze-Rijen airbase, many of which have been used in NATO missions in AFghanistan in recent years.
The shooting-down of one of the helicopters could therefore have significant symbolic importance in the eyes of Islamist terrorists.
There was no confirmation of the report from the authorities.
Police arrested 12 men of Somali origin on December 24 in the port town of Rotterdam, though six suspects have since been released for lack of evidence.
A decision on the fate of the six men remaining in police custody was due to be made on Tuesday.
Police found no explosives or weapons in raids conducted at the same time as the arrests, despite a warning from the AIVD that a terrorist attack was imminent.