Three federal policemen were shot in Mexico City's international airport on Monday by men wearing what appeared to be police uniforms.
Conflicting reports have been released, with some saying all three officers were killed and others saying only two are dead and one was injured.
The policemen had gone to the airport "to detain suspects linked to drug trafficking at Terminal 2," the federal Public Safety Department said in a statement, according to the Associated Press, without specifying if the suspects were also officers. "Upon seeing themselves surrounded by federal police, they (the suspects) opened fire on the officers."
More from GlobalPost: Mexico bar shooting kills 15
BBC News reported that the two men opened fire in the airport's main building food court, sending witnesses running and ducking for cover. The witnesses said they heard around a dozen shots fired and security guards cordoned off the area after the shooting.
No suspects had been arrested following the shooting, which took place shortly before 9 a.m. (10 a.m. EDT, 2 p.m. GMT), said the AP.
Mexico City has relatively low murder rates compared to the rest of the country, where drug violence is rampant and has killed around 55,000 people in the past five and a half years, according to Reuters. But attacks seem to be closing in on the capital recently, with more than 300 gang killings last year.