The Japan Coast Guard says they will not charge the 14 Chinese detained after landing on the Diaoyu Islands in the East China Sea.

And they will possibly be allowed home on Friday. All 14 of them were transferred by the Japanese government to Naha, Okinawa on Thursday. It's been confirmed that they are in good health.

Shouting "Japan get out of the Diaoyu Islands! Diaoyu Islands are Chinese territory", the detained Chinese have been escorted to Naha Port by Japanese coastguard patrol boats.

An activist who landed on the Diaoyu Islands is taken into police custody in Naha, the capital of Okinawa, on Thursday. [Agencies]

They were detained by Japanese police on suspicion of so-called "illegal entry" after seven of the activists landed on one of the Diaoyu Islands Wednesday afternoon.

Police say the group have been moved to Okinawa for questioning.

Shintaro Ishihara, Tokyo Governor said, "This was an illegal entry, which is a criminal offence."

Meanwhile, Chinese Vice Foreign Minister Zhang Zhijun has held a telephone conversation with his Japanese counterpart, Kenichiro Sasae. He's lodged a solemn representation and urged Japan to guarantee the safety of the Chinese citizens and free them immediately and unconditionally. It's the second such move by a Vice Foreign Minister in two days. Earlier, Vice Foreign Minister Fu Ying called her Japanese counterpart, Tsuyoshi Yamaguchi, and also summoned Japan's ambassador to China, Uichiro Niwa, to lodge the same requests.

Experts say tension over the issue has heightened since Tokyo's Governor announced plans to buy the islands from their private owner.

Qu Xing, Director, China Institute of INT'L Studies said, "China was the first to discover the Diaoyu Islands and name them. Japan seized the islands when invading Taiwan, though this did not establish Japan's ownership. The detention of the Chinese activists has serious implications. The Japanese government should release them unconditionally, or there's a risk the tension between the sides will escalate."

The activists' detention has sparked protests both in Beijing and Hong Kong.

Elizabeth Quat, Protester said, "I feel it's unacceptable and I feel angry. We have three requests. We request the Japanese government release the activists immediately. Secondly, Japan should get off our land. Thirdly, they should apologise to the Chinese."

The Hong Kong SAR government says it's monitoring developments, and it's called on the Japanese government to ensure the safety of the activists.