The bodies were found near an industrial estate near London. Details about the victims have not been officially released except that one was a teenager.
The 25-year-old driver from Northern Ireland has been arrested on suspicion of murder. While Essex police have not identified him, several U.K. media outlets have named him as Mo Robinson, from Portadown, County Armagh. British police raided two sites in Northern Ireland.
"This is a tragic incident where a large number of people have lost their lives. Our inquiries are ongoing to establish what has happened," Essex Police Chief Superintendent Andrew Mariner told reporters at a press conference. "We are in the process of identifying the victims; however, I anticipate that this could be a lengthy process."
Belgium's federal prosecutor's office says it is clear that the container in which 39 people were found dead had come through the North Sea port of Zeebrugge.
Police escort the truck, that was found to contain a large number of dead bodies, as they move it from an industrial estate in Thurrock, south England, Wednesday Oct. 23, 2019. (AP)
Britain remains an attractive destination for immigrants, even as the U.K. is negotiating its divorce from the European Union. In Parliament, Prime Minister Boris Johnson put aside the Brexit crisis and vowed that human traffickers would be prosecuted to the full extent of the law.
"All such traders in human beings should be hunted down and brought to justice," he said.
In 2000, 58 Chinese nationals suffocated to death in a truck trailer in Dover. In 2004, 21 illegal immigrants from China who had entered the country via shipping containers perished while harvesting shellfish in northern England
Fox News' Lucia I. Suarez Sang, Brie Stimson and the Associated Press contributed to this report