State media warn Beijing will take action after Japanese arrests on Diaoyus

China's state media issued a stark warning to Japan yesterday over interfering in the Diaoyus, with a Communist Party mouthpiece saying Beijing is prepared to take action to defend its sovereignty over the disputed islands.

The rhetoric came as about 30 mainland activists protested at the Japanese embassy in Beijing, demanding China declare war against Japan to claim the islands, known as the Senkakus in Japan.

Waving Chinese national flags, the protestors chanted slogans demanding China take action against Tokyo after Japan arrested five Chinese activists who landed on the islands. Seven others on the boat were arrested "China should declare war against Japan to claim back the Diaoyu Islands," one banner read.

Police stepped up security around the embassy, but the protestors were largely uninterrupted. They presented a letter, with a blade enclosed, addressed to Japan's prime minister, Yoshihiko Noda. "Noda commits a crime that is unforgivable by Chinese people," the letter said. "Your only way out is to cut open your belly with the blade."

Chen Fule , one of the activists, said they had no plan to sail to the islands as they "were having difficulty in renting a boat".

In a move seen as indicating Beijing is preparing to take tough action, a commentary in the overseas edition of People's Daily said China had no reason to tolerate Japan's actions and could respond to the dispute in a way similar to its handling of tensions with the Philippines over the Scarborough Shoal, known as Huangyan Island, in the South China Sea.

Action taken by Beijing over the shoal dispute included curbing imports of bananas from the Philippines, and warnings from officials Beijing was prepared to take necessary action to defend its territory.