Three of the four Japanese construction employees being detained by Chinese authorities on suspicion of entering a restricted military zone were released Thursday in a sign that Sino-Japanese relations may be on the mend.

The move was viewed as a positive step by China to mend the tattered bilateral relationship, which was strained by Japan's arrest last month of a Chinese trawler captain whose boat collided with Japan Coast Guard vessels near the disputed Senkaku Islands in the East China Sea.

But Foreign Minister Seiji Maehara stressed that one of the Fujita Corp. employees is still in captivity and that he will demand his release.