The State Border Guard Service (VSAT) said its officers detained 11 illegal migrants near the village of Stakai after receiving a tip that a group of "suspiciously looking" people were walking along a road.
The migrants – seven men, a woman and three children – had no documents, but said they were Iraqi citizens.
The border guards inspected the area where the Iraqis had illegally crossed the border from Belarus and found another four men who also said they were Iraqi citizens.
All the detained migrants have applied for asylum in Lithuania, according to VSAT.
The five Afghan citizens, born between 2003 and 2009, were found in the semi-trailer of a Renault truck that was pulled over by police on the Kaunas Western Bypass on Thursday afternoon, the Police Department said.
The Afghans have been handed over to VSAT.