Europol has arrested suspects in Belgium and Paris accused of human trafficking in a probe that was prompted by the UK lorry tragedy last year.

Europol confirmed the arrests in a statement on May 27 and said that "the operation tracked the criminal activity of people smuggling across the continent and was prompted by the tragic discovery of 39 deceased Vietnamese nationals inside a refrigerated lorry in Essex in the United Kingdom in October 2019."

On October 23, 2019, English police found 31 men and eight women dead inside a lorry's refrigerated container. Three minors were among the dead on the truck, which entered the UK from a port in Belgium. An inquest heard that the victims died due to a combination of overheating and a lack of oxygen. 

Two men from Northern Ireland - Maurice Robinson and Ronan Hughes - have both been charged for their involvement with the October 2019 tragedy that saw 39 Vietnamese migrants die in the back of a refrigerated lorry in Essex, UK. Robinson has pleaded guilty to manslaughter, while Hughes remains in custody awaiting possible extradition to the UK.

Co Down native Eamonn Harrison is also a suspect in the case.

Read more: 39 Vietnamese found dead in lorry identified - ten teenagers among them

Eurojust and Europol, the EU's law enforcement agencies, set up a task force - the Joint Investigation Team - to investigate human trafficking in Europe following the discovery of the bodies in October 2019.

On May 26, authorities in Brussels and Paris conducted a number of early morning raids as part of two legal investigations into the human trafficking of "irregular" migrants in Europe. 

Europol said: "The operational activities led to the arrests of 26 suspected members of the criminal network (13 in Belgium and 13 in France) and the seizure of three vehicles, cash and electronic equipment.  

"In total, 21 irregular migrants were found and put to safety."

Europol said that the suspects likely transported "up to several dozen people every day for several months."

While Europol said that the UK lorry tragedy prompted their task force, Essex Police, who are overseeing the investigation into October's incident, said the arrests this week are not related to their investigations.

"We would like to reiterate that, although the Joint Investigation Team was founded in the wake of the tragedy in Grays on 23 October 2019, today's arrests are not linked to our ongoing investigation," Essex police said in a statement, according to RTE.

An Essex police spokeswoman said that Tuesday's arrests were part of a much wider investigation into human trafficking gangs. 

Read more: Essex lorry deaths: Northern Irish man pleads guilty to manslaughter