Just hours after the latest close military encounter between the US and China, when the US navy sailed a destroyer to within 12 nautical miles of the contested Spratly Islands in the South China Sea as a "freedom of navigation" operation - a move that China condemned as a "severe provocation" just as the two countries launched an all-out trade war - the Chinese military launched its spring combat readiness drills with an air force exercise in the West Pacific and a joint combat patrol mission in the South China Sea.

The air force drills include H-6K bombers and Su-30 and Su-35 fighters, according to the PLA , and have a simple, if clear, purpose: "Air Force exercises are rehearsals for future wars and are the most direct preparation for war," the Chinese Air Force said on its Weibo account on Sunday, according to Reuters.

"The more exercises China practices far from its shores the better it will be positioned as an important force for managing and controlling crises, containing war and winning battles", it added.

A Chinese Su-35

Additionally, the PLA Navy is holding drills in the South China Sea to test the navy's combat readiness, China Central Television reported on Friday. It quoted the PLA Navy as saying the drills are routine and do not target any country, although the message had one clear recipient: USA.

"The South China Sea and East China Sea will be primary battlegrounds. The PLA is committed to be battle-ready through simulated combat training," Song Zhongping, a military expert and TV commentator, told the Global Times on Sunday.

"The 2018 drills will be routine and will be held every month, unlike in previous years," Song said, adding that drills were usually held in spring and autumn.

The Global Times reported that "the drills come as the situation in the South China Sea stabilizes." However, the Chinese state-owned nationalist paper added that "some nations are still trying to stir up regional disputes, Wang Xiaopeng, a maritime border expert at the Chinese Academy of Social Sciences, told the Global Times on Sunday."

Although the drills do not target any specific country, they are focused on enhancing China's capability to safeguard the country's sovereignty, Wang said. News of the drills comes a day after the USS Mustin came within 12 nautical miles of Meiji Reef in the Nansha Islands in the South China Sea.

Chinese President Xi Jinping, has urged the army at all levels to enhance military training oriented to combat readiness and to put military training at a strategic position and as the central work with effective results, the Xinhua News Agency reported.

Xi called on the armed forces to enhance targeted and adversarial training, improve actual combat ability, and firmly grasp the capability to win battles.

The Air Force even released a photo of a Su-30 fighter jet on Sino Weibo during its drills. The caption read, "It's spring time. Let's spread the wings across the ocean." By releasing the photo, the PLA Air Force demonstrated its confidence in the open-sea training and the use of weapons, Song said.

The routine military drills in 2018 will focus more on the use of high-end weapons, especially in an electromagnetic environment, as well as on combined forces training, Song added.

As a strategic force, the air force has extended its activities from inland to the deep ocean, it said on Weibo. The air force has become a key force in shaping situations, controlling crises, constraining wars and winning battles, it said.

And so with the US and China already engaged in escalating trade war, it appears that Beijing is preparing for the next step.