Legendary boxing promoter Bob Arum has said he will sever all ties with Tyson Fury's advisor Daniel Kinahan.
Kinahan founded MTK Global in 2012, which represents a number of boxing's top fighters.
He was sanctioned yesterday by the US government and named as part of an organised crime group accused of smuggling cocaine.
The US government is offering $5 million (€4.6 million) for information on the Kinahan crime gang or for the arrest and conviction of its leaders.
It comes as a US government department imposed sanctions against seven senior members of the Kinahan crime gang as part of a bid to target their financial operations.
Bob Arum, who is Tyson Fury's co-promoter, has said he will cut all ties with Kinahan.
Mr Arum told Newstalk: "Frankly I was very surprised because I didn't realise that the United States was involved in that activity - so it really surprised me."
"I was surprised because I had no inkling that it was coming down, that there was any type of US involvement here.
"I knew all of the accusations from the Irish side of it - the Irish media and all of that - but I didn't even contemplate that the US would be involved."
He added: "I can't talk, nor would I talk, about his dealings with us - but when my government makes a statement like they made, as a law abiding citizen of the United States, I have no other alternative but to abide by their determination.
"I can't deal with him in the future because of the position of my government.
"Unless something obviously dramatically changes, which I can't foresee, I will not do business with Kinahan based on these assertions by my government."