China on Tuesday continued its diatribe against Japan over the arrest of a Chinese fishing captain and demanded his immediate release.

"Japan provoked this situation and Japan should take all responsibilities," said Ministry of Foreign Affairs spokeswoman Jiang Yu. "We urge the Japanese to stop so-called legal procedures and let him return safely and immediately."

The captain's fishing trawler crashed into two Japanese patrol boats last week off the disputed Diaoyu Islands, in the East China Sea. He remains in custody, accused of obstructing Japanese public officers while they performed duties.

Their detention angered Beijing, which repeatedly summoned the Japanese ambassador, demanding their release.

Beijing says the Diaoyu Islands and most of the South China Sea belong to China, disputing neighboring countries' claims. The clash over territorial waters and islands -- and the natural resources that go with them -- is a flashpoint in the Asia-Pacific region.

"Chinese people have expressed strong indignation to this, and this fully embodies the Chinese people's resolve to defend national sovereignty," Yu said. "The islands has sovereign rights, and no one can change that fact."

"If you read history documents, Chinese first discovered the island and put it in effective administration," Yu added.

Word of the fishermen's arrest has led to irate reactions from some of the Chinese public, as seen in online posts.

On Sunday, a Japanese school in northeastern China was fired on with small BBs, presumably in connection with the fishermen's arrest.

The Japanese Embassy in China said: "We have received report from Japanese School of Tianjin. The Japanese Embassy contacted relevant departments of Chinese government, requiring relevant departments to strengthen security at the school, to guarantee the safety of the students at Japanese School, as well as all the Japanese in Tianjin."

"So far, we haven't heard that anyone is injured, and we haven't got any result of the investigation," the embassy added.