China steps up anti-carrier missile tests: US commander

China is stepping up efforts to deploy a "carrier-killer" missile system, the commander of the US Pacific Command has said in an interview with a Japanese newspaper, published Tuesday.

"The anti-ship ballistic missile system in China has undergone extensive testing," Admiral Robert Willard told the Asahi Shimbun in Honolulu, according to a transcript of the interview on its website.

Willard said China appeared to have achieved "initial operational capability" but it would take "several more years" before fully deploying the system.

US military analysts have warned China is developing a new version of its Dongfeng 21 missile that could pierce the defences of even the most sturdy US naval vessels and has a range far beyond Chinese waters.

Washington has expressed rising concern over China's military intentions following a string of double-digit increases in Chinese military spending and the rapid modernisation of its armed forces.

In the interview, Willard also said China aims to become a global military power by extending its influence beyond its regional waters.

"They are focused presently on what they term their near seas -- the Bohai, Yellow Sea, South China Sea, East China Sea," Willard said.

"I think they have an interest in being able to influence beyond that point, and they have aspirations to eventually become a global military," he said. "In the capabilities that we're seeing develop, that is fairly obvious."

Referring to tensions on the Korean peninsula, Willard warned that North Korea is ready to take another provocative step and called on China, Pyongyang's sole major ally, to play its role in defusing the situation.

"I think, for now, we're past this particular crisis, but we have no doubt, given North Korea's history, that a next provocation is readied," Willard told the daily.

"It's a matter of assessing how it might be deterred or how the North Koreans might be dissuaded from exercising the next provocation," he said.

"We think the US-Republic of Korea (South Korea) alliance is part of that deterrence effort," he said. "We think the international community and China in particular are another part of it."

Tensions have been high following the North's shelling of a South Korean border island, which killed four people, including two civilians. The South's forces are on alert for any fresh attacks.