The United States has decided to disinvite China from participating in the Rim of the Pacific naval exercise, held near Hawaii, according to a statement from the US Department of Defense.

In recent years, China has participated in certain parts of the training, including submarine safety and other non-warfighting components of the exercises.

The decision to withdraw the invitation extended to China was made in response to Chinese activity in the South China Sea, defense department spokesman Lieutenant Colonel Christopher Logan said, according to a report in USNI.

“The United States is committed to a free and open Indo-Pacific. China’s continued militarization of disputed features in the South China Sea only serve to raise tensions and destabilize the region. As an initial response to China’s continued militarization of the South China Sea we have disinvited the PLA Navy from the 2018 Rim of the Pacific (RIMPAC) Exercise. China’s behavior is inconsistent with the principles and purposes of the RIMPAC exercise,” Logan said.

“We have strong evidence that China has deployed anti-ship missiles, surface-to-air missile (SAM) systems, and electronic jammers to contested features in the Spratly Islands region of the South China Sea. China’s landing of bomber aircraft at Woody Island has also raised tensions,” he continued.

“We believe these recent deployments and the continued militarization of these features is a violation of the promise that President Xi [Jinping] made to the United States and the World not to militarize the Spratly Islands.”

The decision marks another change in US security policy reflecting a deterioration in US-China ties. Despite tensions in 2016, then-Defense Secretary Ash Carter explained the decision to invite China to RIMPAC.

“Our approach to security in the region, as I indicated there, has always been to try to include everyone, so that’s our basic approach,” Carter said. “So if the Chinese want to participate, I think it’s the right place for us to be,” he added.

China’s involvement had, however, long been controversial in the United States, notably, when the Chinese navy was accused in 2014 of using a surveillance ship to gather intelligence during the exercise.