China’s action to impose reporting requirements for ships going through what it claims to be its territorial waters, including in the South China Sea, is “very concerning” and could trigger “instability and potential conflict” if implemented, a ranking United States Coast Guard official said over the weekend.

Speaking at the Asia-Pacific Media Hub virtual forum, US Coast Guard Vice Admiral Michael McAllister said China’s reported plan to require such reporting for innocent passage to the South China Sea “seems to run directly counter to international agreements and norms”.

“If our reading is correct, these are very concerning, and that’s because they begin to build foundations for instability and potential conflicts if those are enforced,” McAllister told international journalists participating in the online forum.

In a newspaper report last week, Chinese authorities were quoted as saying that they will require a range of vessels “to report their information” when passing through what China claims as its “territorial waters”, beginning from September 1.

“Vessels from foreign countries, including submersibles, nuclear vessels, entering Chinese territorial sea shall be required to report info such as their name, current position and next port of call to Chinas maritime administration starting September 1,” the pro-Chinese Communist Party newspaper Global Times said in a tweet on Aug.29.

The Global Times added that China’s Maritime Safety Administration will “deal” with any vessel that fails to report as required “according to relevant laws, regulations, rules and provision”.

More than $5 trillion trade passes through the South China Sea. In July 2016, the Permanent Court of Arbitration ruled in favor of the Philippine petition invalidating China's expansive nine-dash line claim in the South China Sea.

Amid the threat of China’s implementation of this new regulation in the South China Sea, McAllister said the United States is working with its partners across the region to support key partners that are growing increasingly concerned over what he described as China’s “aggressive and sometimes coercive actions”.

The US coast guard official was apparently referring to its regional partners like the Philippines that currently lack the capability or capacity to adequately respond to China’s actions.

“As you all know, the South China Sea is really a maritime superhighway, and coast guard-to-coast guard cooperation really is critical in that region for building good maritime governance. And as I had mentioned in my opening, we’re definitely seeing increased interest in partnering with the United States Coast Guard on maritime safety and security capacity development,” McAllister said.

Also last week, the US Coast Guard cutter Munro conducted a joint maritime exercise with the Philippine Coast Guard and the Bureau of Fisheries and Aquatic Resources in the South China Sea. The bilateral operations with Philippine forces involved four vessels and a helicopter and the USCG’s Unmanned Aircraft System (UAS) Scan Eagle.

The recent exercises included search-and-rescue, fisheries enforcement, and maritime domain awareness, which is meant to enable to identify activities going on in the country’s sovereign waters and to be able to respond to any threats.

“One thing that we are working with the Philippines on in particular is giving them the capacity and the capability to spend more time beyond their littorals, and by that, I mean further from shore,” he said.