A joint navy-air force exercise to practise an amphibious assault and landing was held earlier this month by the People's Liberation Army's Nanjing Military Command, the PLA Daily reported yesterday, amid rising tension between China and Japan over territorial claims to the Diaoyu islands, which the Japanese call the Senkakus, in the East China Sea. The PLA drill started on the south China coast at dawn on August 10, when amphibious assault squads were ordered to board landing ships berthed two kilometres offshore, the report said. With a squadron of attack aircraft providing cover, the landing fleet proceeded though a waterway sown with anti-ship mines, the report said. The warships found themselves under enemy attack almost immediately, PLA Daily said, adding that the assault force made a successful beach landing after bombing the battlefield with heavy artillery. The report was made public after protests from Beijing against any US intervention in the territorial disputes, lodged by Lieutenant General Cai Yingting , a PLA deputy chief of general staff, during a visit to Washington over the weekend. Anti-Japanese sentiment on the mainland has reached boiling point, with protests erupting in many cities in the past two weeks. Mainland web users appeared excited by news of the military exercise. "Does it mean that the PLA are strong enough to straighten out our territorial issue?" one wrote. Others posted on bulletin boards that they were encouraged by such operations, simply because a military drill was much better than empty talk. Antony Wong Dong, a Macau-based military affairs commentator, said the report of the PLA exercise appeared to send a signal to Japan. "Particularly when the cross strait relations between Beijing and Taipei are much warmer, such exercises are in no doubt directed against the Japanese," Wong said. "By making public an already completed military exercise, I'm convinced that Beijing is trying to make known its stance [of claiming sovereignty of the uninhabited but supposedly oil-rich islets] in a more explicit way and to warn the Japanese side to restrain itself over the sovereignty controversy as well."