A graduate waves the Republic of China flag from Taiwan in the crowd during commencement ceremonies at the U.S. Air Force Academy in Colorado Springs, Colorado, U.S., May 30, 2019. Jonathan Ernst, Reuters

BEIJING - The United States is "playing with fire" with its support for self-ruled Taiwan, China said on Thursday, in angry comments ahead of a meeting between Defense Minister Wei Fenghe and acting U.S. Defense Secretary Patrick Shanahan.

The two countries, locked in an escalating trade war, are also at odds over a series of strategic issues, from the disputed South China Sea to democratic Taiwan, claimed by China as its sacred territory, to be taken by force if needed.

Wei and Shanahan - who on his first day as acting defense secretary in January said the U.S. military would focus on "China, China, China" - are both attending the annual Shangri-La defense forum in Singapore which begins on Friday, where they are expected to meet.

China has been particularly incensed by recent U.S. Navy patrols in the Taiwan Strait, U.S. legislation in support of Taiwan and a meeting between Taiwan's national security chief David Lee and White House national security adviser John Bolton.

Speaking at a regular monthly news briefing, Chinese Defense Ministry spokesman Wu Qian described military ties between Beijing and Washington as generally good.

But he took a much darker tone when asked about U.S. support for Taiwan, an issue China has long described as the most sensitive in relations between the two countries.

"Recently, the U.S. sides has been continually playing the 'Taiwan card', trying in futile to 'use Taiwan to control China'. This is deluded," Wu said.

"The series of actions the U.S. side has taken is playing with fire, seriously harms the development of military relations between China and the United States, and seriously harms peace and stability in the Taiwan Strait area."

Taiwan's air, sea and land forces conducted an exercise to repel an invading force on Thursday, as its defense minister pledged to defend the island against what it sees as China's rising military threat.

Washington has no formal ties with Taipei, but is its most important international supporter and main supplier of arms.

A senior U.S. defense official said the fact that Shanahan was going to the Shangri-la dialogue during a period of tension with Iran was a sign that the United States was committed to the region and its allies.

During a meeting with Wei, Shanahan is expected to bring up better communication between the two militaries to avoid the risk of miscalculation, the U.S. official said.

While Wei will likely tackle the Sino-U.S. trade dispute and the hardening Trump administration approaches to Taiwan and the South China Sea, Asian states will be looking for calming messages, according to security experts and regional diplomats.

"Regional countries will be expecting reassurances that China's intentions are in fact peaceful given its growing military might," said Singapore-based regional security analyst Ian Storey.

Storey, of Singapore's ISEAS Yusof Ishak Institute, said Wei must also speak to his domestic constituents, given the fact his address and a rare question-and-answer session are expected to be shown prominently in China.

"In the current environment maybe they won't want him to be too accommodating. He can be expected to blame the U.S. for growing tensions in the South China Sea and there is no way he is going to admit that China is part of the problem."