The Chinese navy announced 10 days of military training in the waters near eastern Hainan Island in the South China Sea starting on Wednesday, amid heightened tensions in the region.

During the training, "no vessel is allowed to enter the designated maritime areas", according to China's Maritime Safety Administration, which released the drill plan on Monday.

Tensions in the South China Sea have worsened in recent months.

Over the past weekend, Admiral Scott Swift, the new commander of the US Pacific Fleet, joined a seven-hour surveillance flight over the South China Sea.

China's Ministry of National Defense expressed its opposition on Monday to the frequent and close US reconnaissance of China and said it gravely undermined Sino-US trust.

China also objected last week to the Philippines repairing a warship, which it ran aground in 1999 near Ren'ai Reef in the South China Sea and refused to relocate despite repeated demands from Beijing.

Last month, the Philippines held two military drills, one with the US and the other with Japan, in the South China Sea.

Major General Zhu Chenghu, a professor at National Defense University of the People's Liberation Army, said it is "understandable" that some people might link the coming drill with the recent tensions, but he dismissed any connection.

"For people with military knowledge, they'd certainly know that a military drill of this scale will take at least three to four months of preparation, or maybe even longer. Dozens of projects will be done during the training to test the navy's tactics and weapons." Zhu said.

"Of course, no country will conduct military training without any purpose," he added, "but this time there is no evidence to subjectively link an ordinary drill to a third party."

Zhang Junshe, a senior researcher at the PLA Naval Military Studies Research Institute, said China's frictions with the US and the Philippines in the South China Sea have been noted almost every month since January, allowing people to speculate every time China held a drill.

"There is no direct connection. China is simply working on an annual military training plan that targets no other nation," Zhang said. "The purpose is simple: to improve our navy's offshore defense combat capability."

Xu Liping, an expert on Southeast Asian affairs at the Chinese Academy of Social Sciences, said the drill is China's legitimate act within its own territory and has "nothing to do with the tension in the South China Sea".

"It is a normal exercise of sovereignty. China wants to modernize its navy to make sure it has the capability to protect its islands and waterway," Xu said.

The Ministry of National Defense did not respond to calls or fax for comments on the training exercise by press time. The ministry told China Daily on Monday that peace and stability in the Asia-Pacific region is in all parties' interests.

Yang Yixi contributed to the story.