Law enforcement agencies, including the FBI, have been knocking on the doors of activists and community organizers in Cleveland, Ohio, asking about their plans for the Republican National Convention in July.

As the city gears up to welcome an estimated 50,000 visitors, and an unknown number of protesters, some of the preparations and restrictions put in place by officials have angered civil rights activists. But the latest string of unannounced home visits by local and federal police marks a significant escalation in officials’ efforts to stifle protest, they say.

“The purpose of these door knocks is simple: to intimidate the target and others in efforts to discourage people from engaging in lawful First Amendment activities,” Jocelyn Rosnick, a coordinator with the Ohio chapter of the National Lawyers Guild, wrote in a statement denouncing the home visits.

More than a dozen people in the Cleveland area have reported being visited this week by local police, the FBI, Department of Homeland Security, and Secret Service.

Michael Nelson, an attorney and the president of the Cleveland chapter of the NAACP, said that police officers visited the parents of one of his clients, a young woman who was among 71 people arrested in May 2015 following the acquittal of a police officer in the deaths of two unarmed people.

When the parents asked whether their daughter was in trouble and why they wanted to speak with her, the officers replied that they wanted to ask “about any information she might have about anybody engaging in violence, planning violence for the RNC.” Nelson and others have asked for a meeting with the agencies involved in the door knocks.

“Maybe we need to have a discussion about the Constitution,” he told The Intercept. “Last time we heard of anything like this was when Dr. King and J. Edgar Hoover were around.”

The FBI confirmed that visits have taken place. “In preparation for the upcoming RNC, the FBI, along with our federal, state, and local partners, has been working collaboratively with members of the community,” a spokesperson for the FBI’s Cleveland field office told The Intercept. “As part of this preparation, law enforcement is reaching out to individuals known in the community who may have information that could help ensure a safe and secure environment during the RNC.” Cleveland’s police department did not respond to requests for comment.

Maggie Rice, an organizer with Food Not Bombs, said that members of her group were visited by police but felt too “rattled” to speak to a reporter. The group is not planning to stage protests but has applied for permits to be in the RNC event zone in order to feed both protesters and Cleveland residents dealing with disruptions to public transportation and services like Meals on Wheels.

“A lot of Cleveland’s most vulnerable residents will be at risk,” Rice said. “The idea that the FBI would be coming in, knocking on our doors and asking questions of people that they know are not involved in organizing any protests and that are basically a humanitarian organization is completely unacceptable and very disturbing.”

“One FBI agent and one plainclothes Cleveland police officer, both white men, showed up and started asking questions about other Food Not Bombs members and our activities,” Rice said. “I personally believe that this is an attempt to intimidate because they know we play a vital role in helping people stay out longer and have their voices heard.”

In other visits, officers asked about people’s previous addresses, political and social affiliation, and convention plans, according to the NLG. “We are concerned these visits will chill the free speech activities of individuals wishing to lawfully protest,” said Rosnick. “And that individuals who are not planning to be involved in the RNC are being harassed due to their associations.”

The group is holding free legal training sessions for local activists and residents and has been monitoring law enforcement preparations ahead of the convention. To Cleveland organizers, the recent door knocks are just a reminder that they are being watched.

“Cleveland is no stranger to FBI interference and FBI entrapment,” said Rice. “I’d say most Cleveland activists and support organizations like ours are aware that every room we’re in probably has an FBI agent in it. And we act accordingly.”