A massive police operation featuring armoured vehicles, a security vault and a 24-hour watch is guarding the belt that is to be awarded to the winner of the upcoming boxing match between Floyd Mayweather and Manny Pacquiao.
The belt for Saturday's 'Fight of the Century' in Las Vegas was made in Mexico with gold and 3,000 emeralds and is valued at $US1 million ($A1.25m) dollars.
Federal agents picked it up from a workshop in the Mexico City suburb of Ecapetec, where it had been handmade.
They took it to a vault at the police headquarters, where it was kept for four days under a permanent watch.
On April 21, an armoured vehicle took it to a forum in Mexico City where Mexican official Mauricio Sulaiman, president of the World Boxing Council (WBC), presented it to the public.
Police did not specify, but the belt is believed to have been taken back to the vault after the event.
"Finally, on Saturday April 25, an operation was carried out to take it to the boarding area at Mexico City International Airport," Mexican police said on Wednesday.
At the airport, it was again handed over to Sulaiman, who took it with him to the United States, with a presentation in New York ahead of the much-anticipated bout.