A US federal judge has ruled that the online news "clipping" service Meltwater violates copyright law by using excerpts from Associated Press articles, the parties said Thursday.

The US news organization sued Meltwater, claiming the service infringed on AP's copyright by delivering its articles to clients without paying a subscription fee.

The case has pitted news organizations seeking to protect copyrighted material against digital rights activists who argued that a ruling for the AP would hurt freedom of expression online.

US District Judge Denise Cote ruled Wednesday that Meltwater News infringed the use of AP content, rejecting Meltwater's claim that it was a "search engine" and that its service constituted "fair use" under US copyright law.

Cote said she would consider a request for an injunction in the case.

The AP welcomed the decision.

"For years, all of us have been hearing that if it is free on the Internet, it is free for the taking. That's what Meltwater argued. The judge in this case just rejected that argument," said AP president and chief Gary Pruitt.

"We won on every single argument we made in the case. We are thrilled. This is first and foremost a victory for the public and for democracy."

Meltwater, which was founded in 2001 in Norway and offers businesses the ability to monitor coverage affecting their firms, said it hopes the decision will be overturned on appeal.

"We're disappointed by the court's decision and we strongly disagree with it," said Meltwater CEO Jorn Lyseggen.

"We're considering all of our options, but we look forward to having this decision reviewed by the Court of Appeals, which we are confident will see the case in a different way."

Meltwater was backed in the case by the online activist groups Public Knowledge and the Electronic Frontier Foundation, with legal assistance from Stanford Law School's Center for Internet and Society.

These groups argued that an unfavorable decision would restrict the use and development of services that allow users to find, organize and share public information.

The AP was backed by other news organizations, including The New York Times Co, Gannett Company and the Newspaper Association of America, which claimed Meltwater was inappropriately profiting from the AP's reporting.

The judge said that Meltwater "copies AP content in order to make money directly" from copyrighted material.

"Investigating and writing about newsworthy events occurring around the globe is an expensive undertaking and enforcement of the copyright laws permits AP to earn the revenue that underwrites that work," the judge said in a 91-page opinion.

"Permitting Meltwater to take the fruit of AP's labor for its own profit, without compensating AP, injures AP's ability to perform this essential function of democracy."