Beijing , China ( CNN ) -- 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 . On Monday , his 14 crew members returned to China . The Japanese coast guard freed the crew members after completing an investigation , a coast guard official told CNN . 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 have n't heard that anyone is injured , and we have n't got any result of the investigation , '' the embassy added .
Japan is illegally holding the captain , Japan says . His crew of two returned to China on Sunday , after Japan freed them . Their arrests off disputed islands has angered some in China . A Chinese school in China was fired at Monday , with BBs .