Thirty-three people have been arrested as part of a Europe-wide investigation into the smuggling of migrants from Iran to Britain, the National Crime Agency (NCA) in London said Monday.
The suspects are believed to be "key members" of an organised crime gang that has smuggled hundreds of people across Europe to Britain using fake identity documents, said Chris Hogben, from the NCA's border policing command.
Twenty-four of those arrested, aged between 26 and 45, were detained in Greece after a series of raids in Athens in a joint operation with Greek police, the agency said in a statement.
"All 24 were arrested for their suspected role in a transnational organised crime group believed to be facilitating the smuggling of Iranian illegal migrants from Iran via Turkey, Greece, Spain, France, Germany, Italy, Belgium, Austria, Switzerland, the Netherlands, into the UK," it said.
Investigators believe the group would charge up to 10,000 euros ($11,000, £8,000) per person to supply migrants with false identity papers and arrange their onward journey to Britain.
Four forgery factories, where the group allegedly produced the counterfeited documents, were dismantled in the operation, the NCA said.
Forging equipment, 50,000 euros in cash and hundreds of documents were also seized.
British immigration officials last week arrested nine people suspected of being part of the UK-based arm of the gang, the NCA added.
Those arrests followed a series of raids in Glasgow, Manchester, in northern England, and Northampton, in central England.