The highlight of the PLA drill was the movement via rail and the sending of tanks into ships, which can "notably lift the efficiency of military transportation", said Li Daguang, a military specialist with the University of National Defense.

Li also dismissed speculations linking the exercise to the upcoming joint military drill between Washington and Seoul in the Yellow and East China seas.

"The section of the exercise in the Yellow Sea is a search-and-rescue one targeted at various threats including maritime disasters. It's an ordinary exercise from which I can't detect any signal of discontent over the US-ROK exercise," Li said.

"But such exercises are also meaningful in practical terms, given the current background," said Li Jie, a researcher with the Chinese navy's military academy.

It was not an "entire coincidence" that the PLA's exercise had taken place days before Washington and Seoul was expected to carry out their drill, Li Jie said.

Following continuous pressure from China, Washington announced that it will hold a portion of a planned joint naval operations with the ROK in the East China Sea, and not carry out the drill entirely in the Yellow Sea between the ROK and China as originally expected.

The US also planned to deploy the aircraft carrier USS George Washington to the East China Sea to avoid upsetting China, according to a Wall Street Journal report. The ROK's Dong-a Ilbo newspaper carried information from the country's defense ministry confirming that anti-submarine exercises will be conducted in both maritime areas.

The White House said the high-level meetings on July 21 in Seoul between US Defense Secretary Robert Gates and Secretary of State Hillary Clinton and their ROK counterparts will "discuss and likely approve a proposed series of combined military exercises, including new naval and air exercises in both the East China Sea and the Yellow Sea", which "will send a clear message of deterrence" to the Democratic People's Republic of Korea.

Last week, China said it firmly opposes any foreign warships or planes entering the Yellow Sea as well as adjacent waters that were engaged in activities that would impact on its security and interests.