China's marine corps and other People's Liberation Army (PLA) units launched a joint live fire drill to take back an islet occupied by "enemy forces," a move experts said was aimed at demonstrating China's resolve in safeguarding its sovereignty.

Video footage from China Central Television (CCTV) showed a group of frogmen stealthily landing on a reef to collect "enemy" artillery and stronghold coordinates. With the help of the intelligence gathered, the command center then ordered missile units to provide cover for marine corps troops, who later landed on the reef and engaged in battles to take control of the island.

CCTV reported that the drill helped the troops to practice military skills such as long-range raids, blockage penetration and taking over islands. Armored troops, infantry, reconnaissance, communications, and ballistic missiles units took part in the live drill.

The drill should not be misinterpreted as a threat of initiating a war against Japan, with which China has recently had territorial disputes over the Diaoyu Islands in the East China Sea, Zheng Ming, a rear admiral of the PLA navy, told the Global Times.

"Chinese armies for the past 20 years have engaged in little combat and naturally lack experience, especially when compared with US armed forces, as China vows to rise in peace and put most of its effort into development," Zheng said, noting the significance of live fire drills for the PLA to improve its combat capability.

Other divisions of the PLA, such as the air force and the navy, have also conducted military drills lately. The Hong Kong-based Phoenix TV reported on Wednesday that China's East Sea Fleet and Nanjing Military Command have held a joint drill for island takeover operations.

"The drills are meant to show China's resolve in safeguarding her territorial integrity," Zheng said. "The significance of reporting on the drills is twofold.  It increases transparency in military construction and boosts public confidence."

Zheng's opinion was echoed by Meng Xiangqing, deputy director of the Strategic Research Institute at the National Defense University of the PLA, who told the Global Times that China's peaceful rise will never come at the cost of China's sovereignty.

"The drills are sending a clear signal that the Chinese army is not only determined, but is also capable of defending its country," Meng said.

On Saturday, eight Chinese surveillance ships, including four fisheries surveillance ships, were seen patrolling the Diaoyu waters. One of the surveillance ships said they were involved in legitimate duties in waters under the jurisdiction of China, defying warnings from Japan Coast Guards, reported Kyodo News.