Gunmen dressed as mariachi musicians killed three people and wounded seven others in a square in downtown Mexico City popular with foreign tourists, police said.
The three assailants carried out the shootings shortly before 10 pm on Friday in the busy Plaza Garibaldi, police said.
Neither the motive for the attack nor the identities of the gunmen were known, but the area is located near the Tepito neighbourhood, where a cartel operates that is considered the largest criminal organization in the capital.
Mexico has been hit by a wave of violence since deploying the army to fight the country's powerful drug cartels in 2006.
Since then, more than 200,000 people have been murdered, including a record 28,702 last year.
Another 37,000 people are reported as missing.
