Two Christians claim a police community support officer told them to stop leafleting in an area of east Birmingham where many Muslims live.
The Christian Institute has complained to West Midlands Police the men were told to leave Alum Rock Road.
The US Christians said they were advised they were committing a hate crime by trying to convert Muslims.
West Midlands Police has investigated the complaint and said the officer intervened to defuse a row.
Arthur Cunningham and Joseph Abraham, a pastor at Grace Bible Fellowship Church, in Saltley, Birmingham, had been distributing leaflets in nearby Alum Rock on 19 February when the police support officer (PCSO) intervened.
They claimed he warned them to leave the area, saying: "If you come back here and get beat up, well you have been warned."
Mr Cunningham and Mr Abraham then agreed to leave.
The men, backed by the Christian Institute, have complained to the force, saying their human rights were infringed.
They have also demanded an apology and damages.
A West Midlands Police spokeswoman said the complaint had been investigated by the force.
She said: "The investigation concluded that the PCSO acted with the best of intentions when he intervened to diffuse a heated argument between two groups of men."
The spokeswoman added that following the investigation the PCSO had been offered "guidance around what constitutes a hate crime as well as his communication style".