Chief Executive Leung Chun-ying summoned the Japanese consul-general yesterday amid a flurry of diplomatic protests following the arrest by Japan's coastguard of 14 activists from Hong Kong, Macau and the mainland, who landed on the disputed Diaoyu Islands.
During the summons of the diplomat, Yuji Kumamaru, Leung reiterated that the islands had been China's territory since ancient times. He urged Japan to release the activist and asked the Japan to refrain from taking any action that could endanger the lives and property of Hong Kong people and other Chinese citizens.
Both Beijing and Tokyo also summoned each other's ambassadors to lodge protests. Chinese Vice-Foreign Minister Fu Ying complained to Japanese ambassador Uichiro Niwa about the "unlawful detention" and demanded Tokyo "ensure the safety of the 14 Chinese nationals and immediately and unconditionally release them".
However, Japanese Prime Minister Yoshihiko Noda vowed that those arrested would be treated "strictly" according to Japanese law.
China and Japan - where the islets are known as the Senkakus - both claim sovereignty.
Taiwan's foreign ministry last night also urged Japan to release the activists immediately to help ease tensions and uphold regional stability. It also reiterated Taiwan's claim over the disputed islands.
The diplomatic clashes took place just hours after the activists landed on the island. They departed from Hong Kong on Sunday on an under-supplied fishing vessel, the Kai Fung No2, which was intercepted several times by the Japanese coastguard.
It was understood that those arrested - including eight activists, four crew members and two reporters on board - were being transferred to Naha, the capital of Okinawa prefecture, for detention. They are likely to be charged with illegal entry and be deported back to Hong Kong.
China had warned Japan of dire consequences if it sent navy ships to intercept the activists, a moved that Tokyo had said it might consider, and urged Japan to assure their safety.
Leung last night sent immigration officers to Tokyo to follow up.
The activists had tried to raise the flags of the mainland and Taiwan on the islands after landing, but were soon arrested by Japanese officers.
At least 10 Japanese coastguard vessels took part in the interception attempt. At one point, two Japanese ships bumped the sides of the Kai Fung, while spraying it with water cannons. But the activists made it to the islands at about 4.30pm.
Some mainland analysts said both China and Japan had exercised restraint, attempting to avoid tensions being escalated to a level similar to that in 2010, when Japan arrested a Chinese fishing boat captain.
Johnny Lau Yui-siu, a political commenter, believed the landing was endorsed by mainland authorities.
"China is making a delicate balance in handling the Diaoyu Islands by allowing the activists to protest," he said. "Had it been a mainland vessel landing on the island, it would have meant China had escalated the dispute. But this time it is a vessel from Hong Kong."
Nevertheless, the Chinese Foreign Ministry should take concrete actions to ensure the safety of the Hong Kong activists, said Sun Zhe, a professor of international relations at Tsinghua University.
"Japan may take a firm stance against the activists as it did for the Chinese trawler captain in 2010," he said. During that incident, the arrested captain was sent to Tokyo under threat of being jailed for three years. After diplomatic exchanges, the captain was released after 18 days.
Chen Fule , a member of the World Chinese Alliance in Defence of the Diaoyu Islands, who took part in a protest outside the Japanese embassy in Beijing yesterday, said the group was considering sending another boat to the islands. Another protest is planned today in Beijing.
Agence France-Presse, Reuters