Twenty-five stowaways were found in a refrigerated container in a ferry in the Netherlands, the authorities reported.
The ferry was traveling to Felixstowe in the UK from the Netherlands when the discovery was made at about 19:00 (18:00 GMT). The discovery forced the ship to be re-routed to the port of Vlaardingen near Rotterdam.
The paramedics examined the stowaways at the port before being transported to a police facility. The identities and nationalities of the victims were not immediately established.
The driver of the refrigerated container, in which the stowaways were found, was arrested and is being questioned by the authorities.
The incident comes weeks after bodies of thirty-nine people were discovered in a truck in Essex in eastern London.