New York - Robert Guerrero, set to fight Floyd Mayweather in five weeks, was arrested on Thursday for allegedly trying to take a handgun onto an airplane, prosecutors in New York said.
The 30-year-old Guerrero was arrested at John F. Kennedy Airport on gun possession charges while trying to catch a flight to Las Vegas.
"I hope Mr Guerrero fights better than he thinks," said Queens District Attorney Richard Brown.
"You cannot bring an unlicensed weapon - loaded or unloaded - into this country or this city. And if you do you will be arrested and face felony charges."
Guerrero, 31-1-1 with 18 knockouts, is set to fight fellow American Mayweather, 43-0 with 26 knockouts, for the undefeated star's World Boxing Council welterweight crown on May 4 in Las Vegas.
Guerrero is a former International Boxing Federation super featherweight and featherweight world champion from California, who beat Andre Berto by unanimous decision last November to keep an interim title.
After spending several days doing interviews to promote the upcoming fight, Guerrero was heading to Las Vegas when he tried to take an unloaded pistol onto a plane.
Guerrero reportedly told a ticket agent at the airline counter during check in that he had the weapon in a locked box and the police were alerted. He also had three unloaded high capacity bullet magazines with him.
He told police he also had the handgun with him when he travelled from Virginia to New York on Monday.
ESPN reported that while Guerrero has a permit to carry a gun in his home state, he did not have a license to carry a gun in the state of New York.
Guerrero made a court appearance in New York Thursday and was released. His next court appearance is scheduled for after his fight against Mayweather.
"We are very pleased Robert Guerrero was released on his own recognisance this afternoon in the wake of this incident and that he is on his way back to Las Vegas to continue training for his highly anticipated May 4 bout against Mayweather," said his spokesperson Mario Serrano.
If convicted Guerrero faces up to seven years in jail.