A group of Twitter users has sued Donald Trump and two White House communication aides for violating their constitutional rights by blocking them from Trump’s personal Twitter account after they criticized the president.

The suit, which was was filed in federal court in New York on Tuesday, argues that Trump’s Twitter account, @realDonaldTrump, constitutes a “public forum for speech by, to, and about the President”. The plaintiffs are seeking an injunction requiring Trump to unblock their accounts and cease blocking others on the basis of their opinions.

Since Twitter users who have been blocked cannot read or respond to Trump’s tweets, the suit argues, blocking users for their political beliefs “imposes a viewpoint-based restriction on ... participation in a public forum” and violates the first amendment.

“It’s like barring people at the door of a city council meeting because they criticized your policy,” said Katie Fallow, a senior attorney at the Knight First Amendment Institute, which is representing the blocked Twitter users.

The lawsuit advances novel legal theories about speech and civic participation at a time when Twitter is arguably the primary means of public communication employed by the president of the United States. Trump’s personal account has more than 33 million followers, and his tweets generally garner thousands of replies, dominate the news cycle and set the agenda for public debate.

White House press secretary Sean Spicer, who is named as a defendant in the suit along with White House director of social media Dan Scavino, said in June that Trump’s tweets should be considered “official statements”.

My use of social media is not Presidential - it’s MODERN DAY PRESIDENTIAL. Make America Great Again! — Donald J. Trump (@realDonaldTrump) July 1, 2017

The White House did not immediately respond to a request for comment.

One Twitter user who used to reply to Trump’s tweets is Eugene Gu, a surgery resident from Nashville and one of the plaintiffs in the case.

“I found that I was able to be heard by many people, and that my voice mattered even if I wasn’t a celebrity or politician,” Gu said in a statement of sending tweets in reply to Trump. Gu was blocked by Trump on 18 June, the suit alleges, shortly after Gu questioned Trump’s fitness for the presidency.

Trump just now blocked me for this tweet. Please protect his ego and don't RT it. https://t.co/LatUpnEcjy #BlockedByTrump pic.twitter.com/ZABxZuk0gF — Eugene Gu, MD (@eugenegu) June 18, 2017

“Now I have extremely limited access to the public forum where I once could be heard,” Gu said. “I feel cut off and as though I’m being treated like an outsider in my own country.”

“This isn’t just about Trump, and it’s not just about Twitter,” another plaintiff, Holly Figueroa, wrote in the Washington Post. Figueroa tweets using the handle @AynRandPaulRyan. “It’s about ensuring that as new platforms of communication are developed, and more and more politicians use social media as a primary way to communicate with constituents, we don’t lose our ability to participate in our democracy or exercise our First Amendment rights.”

Some legal experts were skeptical of the argument that Twitter should be considered a public forum when the Knight Institute first raised the prospect of a lawsuit in June.

But Fallow said that her confidence in the case was bolstered by a 19 June supreme court ruling unanimously striking down a North Carolina law that prohibited registered sex offenders from accessing social media sites. In his opinion, Justice Anthony Kennedy described social media as “the modern public square” and mentioned the usefulness of Twitter for Americans to “petition their elected representatives and otherwise engage with them in a direct manner”.

“While in the past there may have been difficulty in identifying the most important places (in a spatial sense) for the exchange of views, today the answer is clear,” Kennedy wrote. “It is cyberspace – the ‘vast democratic forums of the Internet’ in general ... and social media in particular.”