Police in the Danish region of North Zealand said on Monday they would charge 1,004 children and young people for distributing an underage sex video over Facebook's Messenger chat platform.

According to police, only a handful had distributed it several hundred times, whereas most of those charged had only shared it a few times. Most of the sharing took place last fall. 

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The investigation, codenamed Umbrella, involved several police departments from different Danish districts. Over 300 of those charged were from the Danish capital of Copenhagen and its western suburbs. Slightly fewer than 300 cases were recorded in the North Zealand district. One person was even charged in Greenland.

"This is a very large and complex case that has taken a long time to investigate, not least because of the large number of suspects," said North Zealand police lead investigator Chief Superintendent Lau Thygesen. "We have taken the case very seriously, since it has serious consequences for those involved when material of this type is distributed. And that must be stopped."

The video initially came to US authorities' attention after it was flagged by Facebook, as it is obliged to do for any sexual content involving individuals under the age of 18. The tipoff was subsequently passed on to Danish police via Interpol.

Cracking down on 'revenge porn'

The charges come as police and internet companies the world over have come under pressure to clamp down on "revenge porn," where a former spouse uploads intimate photographs or videos of their ex-partner on the internet.

Despite going effectively unpunished for years, authorities and courts have more recently placed a greater significance on such cases, following countless reports of female victims who saw their personal and professional lives destroyed due to such materials being made public. In Germany, anyone found guilty of uploading revenge porn could face a criminal conviction and up to two years in prison.

Read more: In Germany, your ex must destroy nude photos on request

"It is our opinion that young people understand the major consequences for the victims when they share this kind of material," said Flemming Kjaerside, a police superintendent for Denmark's National Crime Center. "But they may not also understand that it is punishable and that they may be sentenced for distributing child pornography."

Kjaerside added that those charged could be placed on Denmark's child offense register for at least 10 years and be subject to a criminal record. That would see them barred from any profession that would involve working with children and potentially deny them entry into the United States.