Three men have been arrested as part of an operation to tackle a people-smuggling network suspected of illegally bringing almost 3,000 migrants into Europe.
National Crime Agency (NCA) officers arrested three suspected members of the network, believed to operate between Iraq and the UK, in Greater Manchester and Staffordshire on Thursday.
A 41-year-old man from Oldham, a 38-year-old arrested in Stoke-on-Trent, and a 35-year-old from Newton Heath, Manchester, were arrested on suspicion of immigration offences.
The 41-year-old, suspected of being the head of the criminal network, is still being questioned, while the other two men have been released on bail.
Officers also arrested a 25-year-old man in Newton Heath on suspicion of illegally entering the UK.
The action coincided with the arrests of two men in the Ghent area of Belgium following several months of joint operational work between the NCA and Belgian Federal Police.
In the Belgian operation, a 15-year-old boy was rescued before he boarded a lorry bound for the UK, an NCA spokesman said.
The swoop followed arrests made last month in Germany and Romania, co-ordinated by Europol and Eurojust.
The spokesman said the network, made up of smugglers, couriers and lorry drivers, is believed to be behind the smuggling of almost 3,000 migrants into Europe during a three-month period last year.
Business premises in Greater Manchester, Lancashire and Stoke-on-Trent were inspected during the UK operation, which involved officers from Greater Manchester Police and Staffordshire Police, Immigration Enforcement and HMRC.
A haul of 165lb (75kg) of hand-rolling tobacco and more than 500,000 cigarettes were discovered during searches.
NCA branch commander David Norris said: "Between the Middle East and the UK lies a network of highly organised criminal groups who smuggle desperate people in dangerous conditions for huge sums of money.
"We believe during this operation we have identified and now disrupted one of the most significant of these groups, and the impact of acting in tandem with our European partners on this operation has meant we have been able to cause permanent damage to a well-established network.
"The NCA takes people-smuggling extremely seriously. It's a crime based on exploitation of the vulnerable and puts the security of the UK's border at significant risk."