BEIJING (Reuters) – A decision by the United States and South Korea to deploy an advanced anti-missile defence system is aimed at defending against North Korea’s missile threat and does not threaten China, a senior U.S. officer said in Beijing on Tuesday.

The United States has repeatedly tried to rebuff anger from China about Seoul’s move to host a Terminal High Altitude Area Defence (THAAD) unit with the U.S. military.

Mark A. Milley, Chief of Staff of the U.S. Army, told his People’s Liberation Army counterpart Li Zuocheng that THAAD was a defensive measure, the U.S. Army said in a statement released by the U.S. Embassy in Beijing.

THAAD “is a defensive measure to protect South Koreans and Americans from the North Korean ballistic missile threat and is not a threat in any way to China”, the statement paraphrased Milley as saying.

South Korea has said, too, that the move is purely to counter growing missile threats from the North and was not intended to target China, but Beijing has protested it would destabilise the regional security balance.

North Korea conducted its fourth nuclear test in January and followed up with a satellite launch and a string of test launches of missiles in violation of UN Security Council resolutions.

China and the United States have been at odds over the disputed South China Sea as well.

Beijing has been upset with U.S. freedom of navigation patrols in the waters there, and the United States has expressed concern about Chinese aircraft and ships operating in a dangerous manner close to U.S. forces.

Milley said the United States wants to maintain open channels of communications with China’s military to “reduce the risk of crisis or miscalculation and candidly address differences”, the statement said.

Milley “reaffirmed the U.S. commitment to adhere to international rules and standards and encouraged the Chinese to do the same as a way to reduce regional tensions”.

China claims most of the South China Sea, through which more than $5 trillion of trade moves annually. Brunei, Malaysia, the Philippines, Taiwan and Vietnam have rival claims.

China’s Defence Ministry quoted Li as saying that THAAD, the South China Sea and Taiwan were all issues Beijing hoped Washington would pay attention to and “handle appropriately”.

China “hopes both militaries can increase cooperation, appropriately handle disputes and manage and control risks”, the statement paraphrased Li as saying.

(Reporting by Ben Blanchard; Editing by Nick Macfie and Paul Tait)