MEXICO CITY — A union official accompanying protesting street vendors was shot to death Wednesday during the demonstration outside city hall in the south-central Mexico city of Cuernavaca, and another trade unionist also was killed, officials said. A TV cameraman and another person were wounded.

Morelos state authorities said the shooting of union official Jesus Garcia came as vendors demonstrated over their possible expulsion from the city’s main plaza. Cuernavaca’s mayor, Francisco Antonio Villalobos, said the other person killed also was a union official but did not release the victim’s identity.

State prosecutor Uriel Cardona said the preliminary investigation indicated the shooting was not aimed at the protesters or media. He said it also appeared that only one shooter was involved and that was the man arrested quickly after the incident.

Bullets hit two other people, including TV cameraman Rene Perez, who was covering the protest. Perez was being treated for non-life-threatening wounds at a local hospital.

Federico Mayorga, the host of the program Perez works for, said violence has gotten out of hand in Cuernavaca, a city popular with tourists because of its mild climate and exuberant vegetation.

“Things cannot go on like this,” Mayorga said.

Authorities did not say what might have motivated the shooting.

Disputes between groups of street vendors and rival unions have resulted in violence in the past, and vendors have also been subjected to extortion by criminal gangs.