A gunman opened fire in the Mexican city of Cuernavaca's bustling central square Wednesday, killing two union leaders and wounding two other people, authorities and relatives said.
The main square in Cuernavaca, the capital of the central state of Morelos, was full of people going about their business outside the state government headquarters when a young man fired multiple gunshots into a crowd.
"We were there just like any other morning," when at least five gunshots rang out, said AFP correspondent David Monroy.
Mexican TV footage showed the presumed gunman fleeing the scene through the square after the attack, as police officers gave chase. He was ultimately captured and arrested.
Authorities have not yet identified him.
Two leaders of the Confederation of Mexican Workers (CTM), Mexico's largest labor union confederation, were killed in the attack.
Businessman and local CTM leader Jesus Garcia, who was badly wounded, died on the way to the hospital, media reports said.
Roberto Castrejon Calderon, a secretary in the CTM and the son of the union's deputy secretary general for Morelos, was also killed, said his father, Roberto Castrejon Campos.
Castrejon Calderon's own son had been murdered in April last year.
The CTM has been involved in a bitter dispute with a rival union, the New Labor Group (NGS), over spaces for street vendors in the square.
Just before the attack, the state government had been holding a meeting with NGS on overhauling regulations for street vendors. Garcia led a simultaneous street protest against the meeting, demanding the CTM also be included in the process.
Castrejon Campos said in a video message posted online that he believed NGS ordered his son killed.
The wounded included a news cameraman, Rene Perez.
Mexico's unions are plagued by corruption and a history of back-room deals with employers and authorities.
The country has been hit by a wave of violent crime in recent years, often linked to drug trafficking.
Since the government deployed the military to fight the country's powerful drug cartels in 2006, more than 250,000 people have been murdered, including a record 33,518 last year.