AUSTIN, Texas - An animal rights activist's "TAMU Rules!" comment hardly stood out on Texas A&M University's Facebook page. Then she tried a more attention-grabbing post, one that described dog research in a campus lab as "torture."

A lawsuit filed Monday alleges the university hid the "torture" comment from its half-million Facebook followers. In the suit, the People for the Ethical Treatment of Animals accuses Texas A&M, one of the largest public universities in the U.S., of weeding out posts containing words associated with the group's protests over animal research.

While the lawsuit is the latest escalation in a long-running PETA campaign against animal research at Texas A&M, free speech experts say the case has broader relevance amid ongoing battles over the First Amendment and social media. President Donald Trump has been sued over blocking his critics on Twitter, and Maryland's governor settled a lawsuit in April that accused him of censoring constituents by blocking Facebook followers and deleting comments.

Texas A&M declined comment, citing the lawsuit. But PETA claims it began noticing last year that some of its posts stopped appearing on Texas A&M's Facebook page depending on the content.

The group said it eventually discovered about a dozen words Texas A&M was blocking from posts or comments on its page, including "PETA," ''dog," ''abuse" and "testing."

"What they can't do is create this forum where private individuals are permitted to speak and then limit that viewpoint," said David Greene, an attorney with the Electronic Frontier Foundation, a California-based digital rights group that is representing PETA in the lawsuit.

Since 2016, PETA has protested medical research at Texas A&M involving dogs with Duchenne muscular dystrophy, a genetic disease that also affects children. In February, Texas A&M issued a statement defending the research, saying it is helping unravel potential cures and that the dogs are "treated with great care and tenderness."

The statement criticized PETA without mentioning the organization directly. "It saddens us that without full knowledge — of what we are doing, how the dogs are treated, and how close we are to an effective treatment — groups have taken a rigid position and are using slander that adversely affects the opinion of those who don't know all of the facts," the university said.

Katie Fallow, an attorney with the Knight First Amendment Institute at Columbia University, said "viewpoint discrimination is the cardinal sin of the First Amendment." But she said courts also take context into consideration and would look to see if the university was applying a neutral standard.

"If the purpose is for people to speak, the primary rule is that government may not exclude people from that," she said.

News from © The Associated Press, 2018