A Japanese man released by North Korea after being detained earlier this month for an unknown reason returned to Tokyo via Beijing on Tuesday following Pyongyang's decision to deport him.

Tomoyuki Sugimoto, who visited North Korea as a tourist, had been in custody for investigation into a crime but the country "decided to leniently condone him," the state-run Korean Central News Agency wrote in an English-language report Sunday.

The nature of the alleged illegal activity was not specified. Pyongyang decided to expel him "on the principle of humanitarianism," KCNA said.