US boxing promoter Bob Arum says 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.
Mr Kinahan was sanctioned on Tuesday by the US government, and named as part of an organised crime group accused of smuggling cocaine.
The US Department of the Treasury has put some family members and associates on an Office of Foreign Assets Control (OFAC) list.
US authorities also announced a $5m (€4.59m) reward for any information leading to the arrest of three members of the Kinahan family.
Reward of up to $5,000,000.00 USD for information leading to the Financial Disruption of the Kinahan Criminal Organisation or the arrest and/or conviction of:
Christy Kinahan Sr
Christy Kinahan Jr
Submit Tips via email to KinahanTCOTips@dea.gov pic.twitter.com/PEafbJkJ8a
— Garda Info (@gardainfo) April 12, 2022
Mr Arum, who is Tyson Fury's co-promoter, told Newstalk Breakfast he will cut ties with Mr Kinahan.
"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".
Asked if he stood over comments he made in June 2020, in which he described Daniel Kinahan as 'an honourable man', he says: "Well no.
"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".
Mr Arum says he has not spoken with Mr Kinahan in a number of months.
"I haven't spoken with him... it's at least two months and it might be three - we haven't communicated."
He adds: "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".