The United States on Tuesday offered a $5 million reward for help arresting the leaders of Ireland's Kinahan drug trafficking gang which it likened to some of the world's most notorious crime networks.

The United States also imposed financial sanctions against gang leaders whom Irish police said had gone from dealing heroin and cocaine in Dublin in the 1990s to operating across Europe.

A wide range of criminality, including more than a dozen murders, is estimated to have generated over 1 billion euros ($1.09 billion).

Daniel Kinahan, one of the three leaders named by U.S. authorities, has been involved in organising high profile boxing fights in recent years. He was credited by world heavyweight champion Tyson Fury with helping broker a potential unification bout two years ago.

"As of today the Kinahan transnational criminal organisation joins the ranks of Italy's Camorra, Mexico's Los Zetas, Japan's Yakuza and Russia's 'Thieves In Law'," Gregory Gatjanis, an associate director at the U.S Treasury Department, told a news conference in Dublin.

'YOU CAN'T HIDE'

The reward was also offered for information leading to the financial disruption of Daniel Kinahan, whom the Treasury said is believed to run day-to-day operations, his brother Christopher Junior and father Christopher Senior, the gang's founder and leader.

All three are in the United Arab Emirates, with whom Ireland does not have an extradition treaty. The U.S. Treasury said the gang frequently uses Dubai as a hub for illicit activities.

Irish police chief Drew Harris said those in the sporting world associated with the Kinahans needed to question that.

A spokesperson for Fury did not immediately respond to a Reuters request for comment.

A lawyer for Daniel Kinahan told the BBC last year he has no criminal record or convictions and allegations about being a crime boss are false. Reuters was unable to contact representatives for the Kinahans.

"To them (the Kinahans) I would say you can run but you can't hide from justice forever. From today they will be running low on money, friends and influence," Harris told the news conference also attended by members of the U.S. Drug Enforcement Administration, Europol and the UK's National Crime Agency.

($1 = 0.9211 euros)