Irish police have assisted an operation in England in which two men were arrested over the supply of drugs and firearms in the UK and Ireland.
Gardaí (Irish police) said it was supporting the National Crime Agency (NCA) in the investigation.
The men, aged 51 and 20, were arrested at Birmingham Airport on Saturday morning.
A property in the Tamworth area and a business in Birmingham were also searched.
The 51-year-old man was arrested on suspicion of conspiring to import and supply drugs, firearms and ammunition as well as money laundering offences.
The 20-year-old was arrested on suspicion of money laundering offences.
Assistant Commissioner John O'Driscoll said An Garda Síochána (Irish police) was "engaging in the most impactful possible co-operation with law enforcement authorities".
He added that the NCA was one of the force's "most important allies".
The NCA said that the "arrest and searches are part of an investigation into the activities of an organised crime network alleged to be involved in the supply of drugs and firearms".
"The investigation is being supported in Ireland by An Garda Síochána and other international partners," it added.