A former Pacific Fleet Intelligence director called on the Trump administration to reassert U.S. military presence in the Indo-Asia Pacific region to deter China from continuing its aggressive campaign of maritime expansion.

Retired U.S. Navy Capt. James Fanell urged President Donald Trump on Thursday to recalibrate U.S. military policy to recognize China as the greatest threat to American national security interests, particularly given Beijing's territorial claims to Japan's uninhabited Senkaku Islands in the East China Sea.

"While Beijing would prefer to not fire a single shot to restore what its leaders claim as sovereign territory, the [People's Liberation Army] has tightened its noose around the Senkaku islands and is now more prepared than ever to be able to conduct a short, sharp war to restore China's perceived sovereign territory," Fanell testified Thursday before the Congressional U.S.-China Commission.

Fanell said the Trump administration needs to send a clear signal to Chinese President Xi Jinping that the United States will take military action against China if it attempts to occupy the pair of Japanese islands.

Defense Secretary James Mattis traveled to Japan in February to reassure officials that the U.S. commitment to defend the country extended to the Senkaku Islands. Mattis cited Article 5 of the U.S.-Japan Security Treaty, which pledges American defense of Japanese territories.

Tensions over the rocky outposts have escalated in recent years with Japanese and Chinese ships regularly operating nearby as Beijing attempts to counter Tokyo’s control.

Fanell recommended in written testimony that the U.S. Pacific Fleet resume routine naval operations in the East China Sea to convey to Beijing that America will no longer act in fear that its actions could provoke China. He said Xi has taken advantage of U.S. reluctance to take action given the potential for provocation as a "tool to manipulate" America.

"The message to China should be that freedom of navigation and free access to ports is a core interest of the United States and that the U.S. is not going to be constrained by Beijing’s threats," Fanell wrote.

He said the Navy, Air Force, and Marine Corps should conduct joint operations with its Japanese counterparts to patrol the Senkaku Islands and send an "unambiguous message" to China that the allied forces have the capability to retake the islands.

He also urged the administration to suspend China's invitation to the biennial Rim of the Pacific military exercises until Beijing alters its aggressive behavior toward U.S. allies, including Japan, South Korea, and Taiwan.

Trump and Japanese President Shinzo Abe released a joint statement in February saying they "oppose any unilateral action that seeks to undermine Japan's" control of the islands, but it is unclear whether the issue was broached when the president met with Xi last week.