TOKYO- Four of the six Japanese men who were detained in China by local authorities in March have been released and returned to Japan, Chief Cabinet Secretary Yoshihide Suga said Thursday.

The Japanese government will continue to urge China to release the remaining two at an early date, Suga told a news conference.

"Protecting Japanese nationals is the most important task for the government," he said.

The six, in their 20s to 70s, were engaged in activities such as hot spring development research in Shandong and Hainan provinces, home to Chinese naval facilities. (Jiji Press)