Ten people, including two Albanian nationals, have been detained after a migrant vessel arrived at a small harbour in Cornwall.
Devon and Cornwall Police said several people were seen disembarking from the boat at Mylor Harbour, near Falmouth, before departing the area in a van on Sunday.
The force added that the two Albanians were arrested on suspicion of immigration offences.
The eight remaining arrests are understood to have been carried out in a separate police force area.
An individual believed to be under 18 was also referred to social services, the Home Office said.
The investigation is being led by Immigration Enforcement.
Devon and Cornwall Police said: “We were called shortly before 3am on Sunday September 27 following a report of a number of individuals exiting a boat at Mylor Harbour, entering a van and then leaving the area.
“Officers attended and arrested two Albanian nationals on suspicion of immigration offences.
“Immigration Enforcement is leading the investigation.”
A Home Office spokesperson said: “Officers responded quickly to an isolated and rare incident at Mylor Harbour, Falmouth.
“Ten individuals have since been arrested. Another individual understood to be under 18 was referred to social services.
“There is an ongoing investigation, and it would be inappropriate to comment further.”
Last week there were two uncontrolled landings on UK beaches, where migrant boats arrived without being intercepted by authorities.
Home Secretary Shabana Mahmood ordered an urgent review by the Border Security Command.
Child, 10, and two women ‘crushed to death’ in Channel crossing attempt
Three migrants, including a child, 'crushed to death' trying to cross English Channel
‘My son and I could lose everything – all because of a Home Office mix-up’
Labour’s two tribes go to war again – can Andy Burnham unite them?
Who is Sir Ranulph Fiennes? The legendary explorer at centre of care home dispute
Young Brighton woman dies on holiday after falling 98ft from waterfall
