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As China flexes its military muscle in the South China Sea, the U.S. is responding with its own show of force that includes ships, fighter jets and submarines, as well as the test launch of nuclear-capable missiles.

According to internal military reports reviewed by NBC News, almost every week brings another display of U.S. hardware in the waters off China, in a response that has only grown more aggressive since the inauguration of President Trump.

A U.S. Navy carrier battle group centered on the aircraft carrier USS Carl Vinson is now moving through the South China Sea, the stretch of Pacific bounded by China, Vietnam and the Philippines.

Three attack submarines, the USS Alexandria, USS Chicago and USS Louisville, have deployed in the Western Pacific in the past month, and at least one has entered the South China Sea.

Also in February, the U.S. sent a dozen F-22 Raptor stealth fighters to Tindal AB in northern Australia, the closest Australian military airbase to China, for coalition training and exercises. It’s the first deployment of that many F-22s in the Pacific.

And if that didn’t get the attention of the Chinese government, the U.S. just tested four Trident II submarine-launched ballistic missiles during a nuclear war exercise, sending the simulated weapons 4,200 miles from the coast of California into the mid-Pacific. It’s the first time in three years the U.S. has conducted tests in the Pacific, and the first four-missile salvo since the end of the Cold War.

The U.S. effort is deliberately broad and overt, according to Pentagon officials, and is meant to be obvious to the Chinese government.

U.S. ambassador to South Korea Mark Lippert fafter a meeting with South Korean officials at the Foreign Ministry in Seoul on March 17, 2015. JUNG YEON-JE / AFP - Getty Images file

Mark Lippert, the former U.S. ambassador to South Korea and deputy national security advisor during the Obama administration, said America is trying to send a message about freedom of navigation, “free and open commerce and [the] rule of law.”

“You have to remember what is stake here is principles,” Lippert told NBC in an interview. “Adhering to those principles has led to the unprecedented economic and democratic growth in the region. The Chinese are challenging our freedom of navigation.”

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In the last decade, China has converted dozens of tiny islands and coral outcroppings – many claimed by other countries — into forward military bases, adding airfields, piers and other facilities. The new bases range from the Paracel Islands in the northern part of the sea, claimed by Taiwan and Vietnam, to the Spratlys in the south near the Philippines and Malaysia. The construction, sometimes on reclaimed land, has extended China’s defensive perimeter hundreds of miles from the mainland.

A satellite image shows what CSIS Asia Maritime Transparency Initiative says appears to be anti-aircraft guns and what are likely to be close-in weapons systems (CIWS) on the artificial island Subi Reef in the South China Sea in this image released on Dec.13, 2016. DIGITALGLOBE / Reuters

In January, Secretary of State Rex Tillerson said during his confirmation hearings that the U.S. would block China’s access to the disputed islands, and send a “clear signal” that “island-building stops.”

Lu Kang, a senior official with the Chinese foreign ministry, told Richard Engel of NBC News that the islands were Chinese territory and China was free to do what it wanted.

Lippert says the Pentagon’s recent actions are meant to checkmate any attempt by the Chinese to exploit any turmoil from the U.S. presidential transition, particularly one as dramatic as that from Obama to Trump.

“During a transition,” he explained, “the Chinese and United States will test each other, feeling around a bit. Is the Obama policy, which has been fairly aggressive on protecting these principles, going to continue, or is there going to be change?

“What this says is that, for now, nothing has changed.”

Two U.S. Air Force F-22 Raptor stealth jet fighters fly near Andersen Air Force Base, Guam, in this handout photo dated August 4, 2010. US AIR FORCE / Reuters

The recent operations are just the tip of the spear. An NBC News analysis of military movements in the region notes other major operations and basing decisions, including:

-- A new, continual bomber presence at Andersen AFB in Guam, after two decades of absence. Last fall, in fact, the U.S. deployed all three of its strategic bombers – the B-52, B-1 and B-2 – at Andersen. It was the first time all three were deployed to the Pacific.

-- Other transits of the South China Sea by U.S. warships and submarines, culminating with this winter’s Vinson transit;

-- The build-up of modernized ballistic missile defense systems in South Korea and Japan as well as increased integration with the militaries of Japan and South Korea.

-- Increased port calls in Vietnam, Indonesia, the Philippines and Brunei, all countries that have challenged Chinese sovereignty over the islands and outcroppings in the region. The U.S. military presence in the Philippines is now bigger than it’s been in 25 years.

-- An almost continual air and naval presence in Singapore, increasingly a major U.S. ally. The littoral combat ship USS Coronado has spent all of 2017 in and out of Singapore. It’s the only forward-deployed ship of this new, futuristic class.

-- Deployment of the new F-35B Lightning II fifth-generation fighters at Iwakuni AB in Japan. It’s the first permanent deployment of the aircraft overseas.

Birds fly by a U.S. Naval littoral combat ship docked on the Mobile River in Mobile, Ala., on Nov. 30, 2016. Brynn Anderson / AP

While some of the operations are primarily prompted by North Korea’s nuclear saber-rattling, all of them are meant to be noticed by Chinese authorities. A senior Navy officer told NBC News that the Trump administration had inherited the Obama “pivot” to Asia. “This is a perfect example of how routine can stay routine or be a flash point for greater tension,” the officer said.

On Tuesday, the Chinese Foreign Ministry acknowledged the USS Vinson’s patrol.

"China always respects the freedom of navigation and overflight of all countries in the South China Sea in accordance with international law,” said Foreign Ministry spokesperson Geng Shuang.

“But we oppose those who threaten and harm the sovereignty and security of coastal countries under the pretext of freedom of navigation and overflight.”

New satellite images show structures built by the Chinese military on islands in the South China Sea. Analysts believe they can house surface-to-air missiles. Center for Strategic and International Studies

The Chinese, of course, have not been inactive. On February 10, U.S. and Chinese military planes had what the Pentagon describes as “an unsafe close encounter” near Scarborough Shoal in the South China Sea. A war of words ensued.

There have also been joint Chinese-Russian naval exercises in recent months. On Tuesday, Reuters reported that the Peoples Liberation Army has nearly finished building two dozen structures on three atolls in the Spratly Islands that U.S. military analysts believe could house surface-to-air missiles, a dramatic uptick in capability.