Six migrants are believed to be on the run after eight people were seen jumping from the back of a Spanish lorry container in Lincolnshire.
Two people were detained by police on suspicion of entering the UK illegally.
A major land and air search is underway to find the other six people.
Officers were alerted at 1.19pm to eight people running down the A17 Main Road in Fosdyke, Lincolnshire. They were seen running toward the Holbeach area.
Police said they were reportedly wearing dark clothing and may be in need of medical treatment.