Two suspects were arrested in connection with a shooting at a gym in the Mexican capital that left four people dead, the city's mayor said Friday.

Two brothers and a man accompanying them were pronounced dead at the Body Extreme gym in the downtown Tepito neighbourhood, Mexico City Mayor Miguel Angel Mancera said.

The gym owner died later at a hospital of wounds received when he confronted the assailants, according to Milenio Television.

State news agency Notimex said two cars parked near the gym were set on fire at about the same time as the shootings, 9.30 p.m. Thursday.

The cars were torched by the shooters, El Universal newspaper said in its web edition.
Mancera attributed the violence in Tepito to an "outbreak of some gangs", ruling out the idea that one of Mexico's powerful drug cartels has established a presence in the capital.

The fatal shooting at the gym appears to be part of "a direct dispute" among a specific group of people, the mayor told Televisa television.