Wales also said he thought the lawsuit, brought Tuesday by Wikimedia and rights groups, would end up in the U.S. Supreme Court because either side is likely to appeal any ruling against it.
A U.S. Department of Justice spokeswoman did not immediately respond to a request for comment on Wednesday.
In the legal challenge to the spy agency, Wikimedia and eight other groups said one of the NSA's mass surveillance programs violates privacy rights and makes people worldwide less likely to share sensitive information.
The U.S. Supreme Court in 2013 rejected another challenge to NSA surveillance of email and other communications, ruling that a similar coalition of plaintiffs did not prove they had been spied upon or would be. The ruling, however, was made just three months before documents made public by former NSA contractor Edward Snowden revealed extensive U.S. spying.
"We have proof that it's actually impacting us from the Snowden documents. Wikipedia was specifically targeted for upstream surveillance," Wales said during a question-and-answer session at a pensions conference in Edinburgh.
The lawsuit takes on what is often called "upstream" collection because it happens along the so-called backbone of the Internet and away from individual users.
One Snowden-released document, which was included in the lawsuit, had the logo of Wikipedia among organizations whose online user data the spy agency was interested in.
"We have other evidence that will be presented in court of the harm that has caused us," Wales said, without elaborating on the evidence.
U.S. lawyers with expertise in national security have called the lawsuit a longshot because of the difficulty of showing harm and because spy agencies are sometimes able to block litigation by citing the need to protect state secrets.
The case is Wikimedia Foundation, et al, v. National Security Agency, et al, U.S. District Court for the District of Maryland, No. 15-662
© Thomson Reuters 2015
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