TOKYO - Japan arrested five activists from Hong Kong who landed on the Diaoyu Islands at around 5:30 pm local time on Wednesday on suspicion of illegal entry, according to police from Japan's Okinawa.

A Japan Coast Guard patrol ship sails around a fishing boat (R) carrying activists from the Hong Kong near the Diaoyu Islands in the East China Sea, in this handout photo taken by the Japan Coast Guard August 15, 2012.[Photo/Agencies]

Two other activists who also landed on the islands returned to the fishing vessel, said the police.

"The five arrested may be transferred to the Immigration Bureau of Japan later and sent back to Hong Kong by the Immigration Bureau," a spokesman from Japan Coast Guard (JCG) told Xinhua.  

The Japanese government summoned Chinese Ambassador to Japan Cheng Yonghua to the Foreign Ministry in Tokyo to lodge a protest, chief government spokesman Osamu Fujimura said.

The Hong Kong fishing vessel carrying eight Chinese activists seeking to assert China's claim to the Diaoyu Islands departed from Hong Kong on Sunday, according to previous media reports.

A fishing boat carrying activists from the Hong Kong sails near the Diaoyu Islands in the East China Sea in this handout photo taken by the Japan Coast Guard on August 15, 2012.[Photo/Agencies]