The North Koreans, who had been living in the northern suburb of Pathum Thani for nearly one month, were being questioned at a local police station, Lt. Col Nikorn Chaivirawong told Reuters.
A South Korean man was also arrested in Tuesday's raid on the Ekpathum Apartments, a five-storey building where the North Koreans had occupied the entire fourth floor.
"He will face charges of bringing illegal immigrants into the country," Nikorn said of the South Korean whom he did not name.
It was not known how the group -- including 15 children -- had entered Thailand, but they may have followed the same route as other refugees, Nikorn said.

Copyright Reuters, 2006