The authorities in the breakaway region of Somaliland say they have detained three Belgian immigration officials in the capital, Hargeisa.
The three arrived on a flight from Ethiopia with a man they had deported from Belgium, Somaliland's Aviation Minister Ali Warran Ade told the BBC.
He said they did not have visas to enter Somaliland or the prior consent necessary to deliver a deportee there.
The minister said they were being held in a hotel pending investigations.
Mr Ade said the deportee had been sent back to Ethiopia on the flight on which he had arrived.
Somaliland declared independence from Somalia after the overthrow of dictator Siad Barre in 1991.
Somaliland's self-declared government is not recognised by any other state, although it is credited with bringing peace and a degree of development to the territory, amid chaos in the rest of Somalia.