The two-time Cup Series champion has joined Richard Childress Racing for 2023 after a 15-year run with Joe Gibbs Racing that yielded both of his titles, won in 2015 and 2019.
The 37-year-old, who finished third in the non-championship Clash race at the LA Coliseum on Sunday, released a statement on Monday responding to reports of his brief detainment in Mexico last month.
"In late January, Samantha and I enjoyed a several day vacation in Mexico," Busch wrote.
"When departing the country, my handgun was flagged during routine screening at the airport.
"I have a valid concealed carry permit from my local authority and adhere to all handgun laws, but I made a mistake by forgetting it was in my bag.
"Discovery of the handgun led to my detainment while the situation was resolved. I was not aware of Mexican law and had no intention of bringing a handgun into Mexico.
"When it was discovered, I fully cooperated with the authorities, accepted the penalties, and returned to North Carolina.
"I apologize for my mistake and appreciate the respect shown by all parties as we resolved the matter. My family and I consider this issue closed."
Following his RCR debut in the Clash, Busch was vocal in his disapproval of driving standards, calling them a "disaster" as rivals showed "disrespect" to their fellow competitors.
Reigning Cup Series champion Joey Logano came in for particular criticism, with Busch calling him "two-faced" after they collided on lap 86.
The 2023 season officially begins on 19 February with the 65th running of the Daytona 500.
