Japan sent a strong message to China last week by enforcing Freedom of Navigation Operations in the South China Sea, which Beijing considers its sea.

That's according to Radio Free Asia report, which claims that Japan's Maritime Self-Defense Force destroyers have conducted Freedom of Navigation Operations in the South China Sea "to warn China."

The report quoted a statement made by a senior Defense Ministry official to Yomiuri Shimbun who said the South China Sea operations were "meant to warn China, which is distorting international law, to protect freedom of navigation, and law and order of the sea."

China considers the South China Sea its sea -- all of it. And it has taken several steps to control the vast sea, like building artificial islands and intimidating its neighbors, and most notably the Philippines, with the presence of hundreds of Chinese vessels near a Philippines-administered island in the South China Sea. That’s in spite of Manila’s winning of an international court verdict against Beijing in 2016.

"Vast expanses of South China Sea have been unlawfully claimed by the Chinese Communist regime following the illegal dredging and filling in of reefs and sandbanks to form artificial islands," said Juscelino Colares, co-director of the Cox International Law Center at Case Western Reserve University. "To date, the Chinese Communist regime has refused to comply with the Permanent Court of Arbitration in The Hague — often referred to as the World Court — which found neither 'historical basis' nor 'historical title' that would justify the exercise of Chinese sovereignty over these disputed waters."

Meanwhile, China's South China Sea ambitions have pitted Beijing against several neighboring countries, including Indonesia, which has drawn a "red line" in the South China Sea, establishing fishing rights in areas where China claims "overlapping" rights.

Then there's Vietnam, which outlawed many of China's ongoing activities in the South China Sea. Like the building of artificial islands, blockades, and offensive weaponry such as missile deployments.

And there’s Malaysia, which has drawn its own red lines against Beijing.

In addition, China's quest to assert control over the South China Sea pitted Beijing against Washington, which considers the South China Sea an open sea, and has taken a couple of steps to contain China's maritime ambitions.

First, it formed AUKUS, an alliance between Australia, the U.K., and the U.S.

"Washington has determined that it can no longer be the police of the planet," said Yannis Tsinas, a former Washington military diplomat.

"It cannot bear the entire cost. That's why American forces pulled out from Afghanistan while they reduce their presence significantly in the Middle-East."  

And has formed additional alliances to share the burden of maintaining regional peace.

Second, it has upgraded the  Quadrilateral Security Dialogue, a strategic security dialogue between the U.S., India, Japan, and Australia, with alliance members sending their navies to conduct Freedom of Navigation Operations to challenge China’s maritime claims.

"Freedom of Navigation operations are a means of formally, and notoriously, challenging excessive maritime claims that a country imposes under the guise of exercising territorial sovereignty," said Colares.

"The idea is that a country can't restrict navigation or overflight rights, along with freedoms or other lawful uses of the sea.

"These lawful uses are protected under the 1982 U.N. Convention on the Law of the Seas."

In the South China Sea disputes, it's apparently China against all -- its neighbors and the international community in a new Cold War, with far-reaching consequences for maritime trade and peace in the world’s fastest-growing region.