China’s President Xi Jinping reportedly put his military advisers overseeing operations in the South China Sea on alert last week, as the crew monitors the situation in the region -- as well as in contested Taiwan.

Xi made his comments to the Southern Theatre Command while he was on his inspection tour Thursday, according to the New Zealand Herald. His comments were released to the public Friday.

“It's necessary to strengthen the mission … and concentrate preparations for fighting a war,” CCTV quoted Xi as saying. “We need to take all complex situations into consideration and make emergency plans accordingly.”

“We have to step up combat readiness exercises, joint exercises and confrontational exercises to enhance servicemen's capabilities and preparation for war,” he added.

Xi’s speech was released a day after China’s Defense Minister Wei Fenghe vowed the country would not give up “one single piece” of its territory and challenges from Taiwan were dangerous.

U.S. Navy Admiral John Richardson asserted Monday the U.S. would continue patrolling the disputed region and that such patrols highlight the U.S. position against “illegitimate maritime claims.”

“We will continue to progress this program of freedom of navigation operations," Richardson said at a press conference in Manila. "We do dozens of these operations around the world to indicate our position for...illegitimate claims, maritime claims.”

The comments come after a Chinese destroyer came close to a U.S. Navy ship during a “freedom of navigation” mission near a contested reef.

The Associated Press contributed to this report.