Three of the four Fujita Corp. employees detained by Chinese authorities on suspicion of entering a restricted military zone returned to Japan on Friday.

The three men are Yoshiro Sasaki, 45, Hiroki Hashimoto, 39, and Junichi Iguchi, 59. China said the fourth detainee, Sadamu Takahashi, 57, remains in custody pending further investigation.

After arriving at Tokyo's Haneda airport in the afternoon, the three men, along with two Fujita executives, held a news conference at the company's Tokyo headquarters. They apologized for the actions that led to their detention and asked the Chinese authorities to release Takahashi soon.