Three May Day protesters were arrested this week for allegedly setting fire to an American flag in a city park, police said.

The three suspects reportedly branched off from a group of 15 protesters before dousing the flag with “ignitable liquid,” around 6:20 p.m., Charlotte Mecklenburg Police said.

Authorities apprehended Landon Rice, 23; VanaMary Isaac, 26; and Dhruv Pathak, 24, the Charlotte Observer reported.

While burning the American flag is considered protected free speech under the First Amendment, setting objects on fire in a city park is not legal, hence the protesters were arrested.

Rice, Isaac, and Pathak face charges of carelessness with fire and injury to real property, police said.

Court records cited by the Observer reveal that Rice and Pathak have been previously charged with minor offenses.

Rice was reportedly charged with resisting arrest and impeding traffic. Pathak has been charged with impeding traffic, resisting arrest, second degree trespass, disorderly conduct and assault on a government official.

May Day is internationally recognized as a day when activists protest the most pressing labor issues of their country. Many activists used the opportunity Tuesday to protest the Trump administration’s policies on immigration.