Two Iraqis suspected of being part of a network which smuggled up to 20 migrants a night into the UK are due in court.
Sleman Ahmed, 33, was arrested in Bordesley Green, Birmingham, while Shamel Zorab, 37, was detained in Eccles, Salford.
The are wanted by the Belgian police for their alleged connections to a Kurdish criminal network which smuggled migrants into the UK on lorries from service stations in Belgium.
They were detained following an operation led by the National Crime Agency (NCA) and supported by the Greater Manchester and West Midlands police forces.
The pair will appear before Westminster Magistrates' Court for an extradition hearing.
They are accused of being in contact with members of the smuggling network and collecting fees from migrants they had brought across the border.
Ten further arrests have been made in Belgium, where a number of suspects are awaiting trial.
The NCA's Colin Williams said: "We believe this crime group is involved in attempting to smuggle people into the UK on an almost daily basis, and our co-operation with the Belgian authorities on this investigation continues.
"With our international partners we will continue to disrupt criminals involved in organised immigration crime, making it harder for them to operate across the UK border and abroad."