The People's Liberation Army (PLA) will launch a six-day, live ammunition drill starting on Wednesday in the East China Sea, a move that analysts said is in response to a joint exercise between the United States and Republic of Korea (ROK) navies in the Yellow Sea.

The PLA decision was issued on June 24 and posted on major Chinese websites on Monday, when the US-ROK drill was scheduled to start. The US and ROK earlier cited the Democratic People's Republic of Korea (DPRK) as the target of their drill. A US nuclear-powered aircraft carrier is also reportedly scheduled to participate in the exercise not far off China's coast.

But the ROK navy announced on Monday that their joint maneuver has been postponed to July.

According to the PLA announcement, all vessels will be prohibited from entering its designated exercise area from midnight to 6 pm, from June 30 to July 5.

"They must follow orders of the Chinese navy to ensure safety," it said.

An officer of the Ministry of Defense said on Monday that the PLA's planned drill is routine. But the Hong Kong-based Mingpao Daily News called the announcement a "rare move" to publicize a military drill days in advance.

Some analysts said the move is clearly related to the presence of aircraft carrier USS George Washington near China's shores, which put major cities including Beijing and China's coastlines under the US carrier's combat scope.

"Though the Chinese government did not say anything about the drill, anybody with common sense on military strategy will bet that they are related," said Shi Yinhong, a senior expert on US studies at Beijing-based Renmin University of China.

Foreign Ministry spokesman Qin Gang said earlier this month that Beijing is seriously concerned about the US-ROK joint exercise and is closely following the matter.

"Under current situations, relevant parties should exercise restraint and refrain from doing things that may escalate tensions and harm the interests of the countries in the region," Qin said.

Ma Xiaotian, the PLA's deputy chief of staff, said at an annual security conference in Singapore on June 5 that one of the major obstacles in China-US military relations is the "high-intensity surveillance of US warships and planes in the South China Sea and East China Sea". US Defense Secretary Robert Gates was also present at the meeting.

The US and ROK said the joint exercise is targeted at the DPRK after the deadly sinking of an ROK warship in March, but it is "still extremely rare for a major power to send an aircraft carrier that close to another major power", Shi said.

"Any large country has its bottom line for military vigilance and pride. The US-ROK drill has drawn angry response from the Chinese public and I think that is one reason behind its delay."

Li Jie, a researcher with the Chinese navy's military academy, said the US-ROK drill will not help ease tensions over the sinking of the ROK warship.

Pyongyang threatened on Monday to bolster its nuclear capability to cope with what it said is a hostile US policy and military threats.

Still, other analysts said the two latest drills are not related as the Chinese navy carried out a similar move last year.

Chen Hu, editor-in-chief of the World Military magazine affiliated to the Xinhua News Agency, said Beijing does not necessarily see the US-ROK exercise as a provocative act.

"Instead, the PLA can take the presence of the giant aircraft carrier fighting group as a 'drill target'," he said.