TOKYO - The plane carrying seven of the 14 Chinese activists arrested by Japan police for landing on one of the Diaoyu Islands Wednesday took off from Naha airport in southwest Japan at around 6:40 pm Friday for Hong Kong.

The other group of seven will return later Friday on the boat they came from, according to a spokesman from Chinese embassy in Japan. But the exact time for them to depart remains unknown.

The Japanese Cabinet announced Friday morning that it had decided to release all the 14 Chinese activists who were arrested on Wednesday after seven of them landed on one of the Diaoyu Islands in the East China Sea.

China's Foreign Ministry said later Friday that China holds a " firm stance" on the Diaoyu Islands, and any of Japan's unilateral moves against Chinese nationals is illegal and invalid.

The 14 Chinese activists, overcoming the obstructions created by Japan Coast Guard patrol ships, arrived at the Diaoyu Islands by a Hong Kong fishing vessel on Wednesday to assert China's territorial claim to the islands.

China on Wednesday lodged solemn representations with Japan on the latter's illegal detention of the Chinese nationals on the Diaoyu Islands, and on Thursday once again urged Japan to " immediately and unconditionally" release the Chinese nationals.