Mexico's Federal Police officers arrive at the scene of a shooting that took place in Mexico City's international airport on June 25, 2012. Two police officers were shot dead at the airport and a third died later at the hospital. (Alexandre Meneghini/AP)

Two days after a deadly shootout at the capital’s busy international airport, Mexican officials sought to calm fears Wednesday, stressing that the facility was fully operational and safe for travelers.

But even as the tourism boosters, including President Felipe Calderon, played down the incident, doubts were being cast on the official explanation for the gunfight that left three federal police officers dead in the food court at Terminal 2 of Mexico City’s Benito Juarez International Airport on Monday morning.

Mexican law enforcement said the shootout occurred as federal police were attempting to arrest members of a drug-trafficking ring at the airport.

Police said two suspected traffickers, “seeing themselves surrounded by federal police,” began shooting as officers moved in. Two officers were killed on the spot, and a third died at a hospital.

Later, investigators announced that the two suspected traffickers were also federal police officers, who escaped in a car and remain fugitives.

Police said the confrontation followed an 18-month-long investigation of federal and local officials suspected of participating in a cocaine-trafficking ring at the airport. Sketches of the suspects have been released, but not their names or photographs, though police say they know the identities.

Mexican media have begun to question the official account, asking whether the gunfight could have been the result of a falling-out among co-conspirators. If it was an operation to capture traffickers in the act, some said, why did it take 20 minutes for additional police officers to appear after the shooting began? Why were only three police officers sent to arrest two armed fellow officers in a crowded airport?

“Tricks, lies, inventions!” the columnist Manuel J. Jauregui wrote in the Reforma newspaper Wednesday, adding that the operation was an embarrassment and that federal authorities were scrambling to get their stories straight. “They don’t even know who were the good guys and who were the bad guys,” Jauregui wrote.

Attorney General Marisela Morales said prosecutors were investigating the infiltration of the airport by drug smugglers. In separate actions this week, police shuttered several currency exchange offices at the airport that were suspected of money laundering.

Police said they have arrested 180 people and confiscated 648 pounds of cocaine at the airport as part of the trafficking probe.

Communications and Transportation Secretary Dionisio ­Perez-Jacome declared that “the airport is safe” and noted that the gunfight occurred outside the restricted area, before passengers are searched. “What’s important is, no tourists were affected,” he said.

Perez-Jacome described the incident as “unfortunate” but necessary. “When you are fighting corruption, fighting the bad guys, you have to keep going forward and taking action,” he said.