Greek police have found 41 people alive in a refrigerated truck in a discovery that has underscored the extraordinary risk migrants are prepared to take to get into Europe, the Guardian has reported.

Reportedly, the truck’s driver, a 40-year-old Georgian national, was arrested. The lorry is believed to have raised suspicion partly because it had no markings or livery.

At least a third were found to have trouble breathing, and seven were rushed to a nearby hospital with respiratory problems.

The vehicle’s refrigeration system had broken down by the time the truck was stopped at a motorway toll station outside the city of Xanthi in north-east Greece and its passengers, of apparent Afghan origin, were discovered.

“A police operation is under way but we believe the lorry entered the country from Turkey,” said Lt Col Theodoros Chronopolous, a police spokesman. “Discoveries of this sort are rare but happening more frequently mainly because migrants want to avoid the islands.”

Chronopoulos said it was thought the lorry was headed inland towards Thessaloniki. “Where the migrants were ultimately destined is not clear,” he said. “Their first stop was Greece, their second elsewhere in Europe. Traffickers and migrants are taking ever greater risks.”