MADISON, Wis. (AP) — A conservative think tank has filed a federal lawsuit against Democratic Wisconsin Gov. Tony Evers, alleging that he violated the First Amendment rights of staff members who were denied access to a press briefing and kept off an advisory list sent to other reporters.

The MacIver Institute for Public Policy filed the lawsuit Tuesday in federal court in Madison alleging that Evers violated its staffers’ constitutional rights to free speech, freedom of the press and equal access. Evers’ spokeswoman, Melissa Baldauff, had no immediate comment Wednesday.

The lawsuit alleges that since Evers became governor in January, he has refused to extend invitations to press events to reporters for the conservative group’s MacIver News Service. It also says MacIver does not receive press releases that are sent to other news outlets.

The exclusions make it harder for MacIver reporters to gather the news in a timely, thorough manner and violates the right of equal access inherent in the freedom of the press, the lawsuit alleges.

The lawsuit alleges that keeping MacIver off the email advisory lists “constitutes viewpoint discrimination based on the MacIver Institute’s editorial stances,” which it says is a violation of its free speech rights.

MacIver is asking the court to issue an injunction ordering Evers to stop barring MacIver from equal access to information on the same basis as other reporters and lists announcing such events.

“Our reporters have the same constitutional rights as every other journalist in Wisconsin, and we have a duty to keep the public informed about what’s happening in state government,” Brett Healy, president of the MacIver Institute, said in a statement.

He said Evers has refused to treat MacIver reporters the same as those from other outlets, forcing them to sue. MacIver is represented by the Liberty Justice Center, a conservative public interest law firm in Chicago.

Bill Lueders, president of the Wisconsin Freedom of Information Council, called the lawsuit’s allegations “deeply troubling.” He said the area of law at issue is complex and he can’t say whether the conduct described is a violation of the law.

“It certainly is not in keeping with the state’s proud tradition of open government,” Lueders said. “If Tony Evers has what it takes to lead state government, he ought to be able to withstand the inclusion and presence of reporters from a conservative news outlet.”

The lawsuit cites an Evers administration budget briefing in February in which two MacIver reporters were denied access but 26 other reporters, including from The Associated Press, Milwaukee Journal Sentinel and Wisconsin State Journal, were allowed in. Evers wasn’t present, but members of his administration provided information to reporters on embargo ahead of his budget speech to the Legislature that evening.

MacIver reporters have attended other news conferences attended by Evers and members of his administration. For example, a MacIver reporter was at the July budget bill signing held in the governor’s conference room and asked Evers a question that the governor answered.