China releases four of six detained Japanese

Tokyo (AFP) - Four Japanese detained in China in March for alleged "illegal activities" have safely returned home, officials said Thursday, though two others are still being held.

Tensions regularly mar Japan-China relations, with a maritime territorial dispute and lingering tensions over Tokyo's history of aggression in the first half of the 20th century the major irritants.

China had already detained five other Japanese citizens since 2015, largely on suspicion of spying.

The four released were among six taken into custody in Shandong and Hainan provinces in March, according to Yoshihide Suga, Japan's chief government spokesman.

"While we are making necessary contact with Chinese authorities, I would like to refrain from commenting on details as there are people who are still detained," he told a regular press conference.

Suga also withheld comment on why the six were detained and why some were released.

Japan's foreign ministry would not say exactly when the four returned, only that it was "confirmed" on Thursday that they were back and well.

Earlier this year, Suga said Chinese authorities had told Japan that the six "violated domestic laws" but offered few details.

The Chinese foreign ministry in May said they were being probed for "illegal activities".

The six are Japanese company officials who visited China after a local company or companies asked them to search for hot springs, public broadcaster NHK and other media have reported.

Japanese media have speculated that the presence of military ports in both provinces may have caused them to be suspected of trying to access intelligence.