The U.S. Navy has again affirmed the People's Liberation Army Navy will be its main adversary in decades ahead.

In a new strategy document, "Advantage at Sea; Prevailing with Integrated All-Domain Naval Power," the commanding officers of the three U.S. sea services said presented the most pressing, long-term strategic threat to the U.S.

The sea services ill move away from their current posture of de-escalation, or strategic patience, to adopt a more aggressive stance against China.

"Ready, forward-deployed naval forces will accept calculated tactical risks and adopt a more assertive posture in our day-to-day operations," said the document.

This 26-page strategic analysis is the first of its kind since the 2015 cooperative strategy for 21st century Seapower.

The strategy instructs the U.S. Navy, the U.S. Marine Corps and the U.S. Coast Guard to work together to prepare for a future, and almost inevitable, high-end war against China. It calls for the sea services to cooperate "with urgency to integrate and modernize our forces as we prepare for the challenges ahead."

"For generations, we have underwritten security and prosperity and preserved the values our Nation holds dear," said the document. "However, China's behavior and accelerated military growth place it on a trajectory that will challenge our ability to continue to do so."

Rear Adm. James Bynum, acting deputy chief of naval operations for Warfighting Development, said the U.S. in the past largely turned away from the antagonistic behavior of China, Russia and others to help de-escalate dangerous situations.

This response will now change with the U.S. becoming "more responsive, more assertive on our own in our operations," he said.

"Advantage at Sea" also points out China is already engaged in operations other than war against the United States. These "gray-zone operations" are daily acts of Chinese aggression both in the real world and in cyberspace directed against the U.S.

All three sea services must also together counter China's ongoing gray-zone operations, and must be given the right tools to defeat China in this bloodless arena of conflict.

"It is clearly signaling that when you have an adversary who is constantly looking to operate below some perceived threshold that we made very clear that we will operate, reinforce and maintain the international standards and rules-based order that we have [had], in the Pacific in particular, for the past 70 years," said Maj. Gen. Paul Rock, the director of the Marine Corps' Strategy and Plans Division.

China's gray-zone operations include attacking military and civilian cyber networks; fielding naval auxiliaries disguised as civilian vessels and militarizing disputed islands and rock formations in the South China Sea.

It also includes boosting its strategic, space, cyber, electronic, and psychological warfare capabilities and pressuring countries economically to build up overseas logistics and basing infrastructure in strategic maritime locations.