The U.S. Navy will reconstitute the inactive United States 1st Fleet into an expeditionary strike force equipped to fight China in the South China Sea and the Indian Ocean.

Secretary of the Navy Kenneth Braithwaite revealed the reactivation of the 1st Fleet along with an operational division of the Indo-Pacific Theater into zones patrolled by both the 1st Fleet and the U.S. 7th Fleet based in Japan.

During a hearing on Navy and Marine Corps readiness at the Senate Armed Services Committee, Braithwaite said the 1st Fleet would be based in Singapore or Australia.

He told senators "the decision has been made (to bring back the fleet), yes."

"In order to improve our posture in the Indo-Pacific we will reconstitute the 1st Fleet - assigning it primary responsibility for the Indo and South Asian region as an expeditionary fleet," Braithwaite said.

"This will reassure our partners and allies of our presence and commitment to this region while ensuring any potential adversary knows we are committed to global presence, to ensure rule of law and freedom of the seas."

He said the 1st Fleet would be an offensive weapon and will be organized as a naval expeditionary force.

As a naval expeditionary force, the 1st Fleet will need support from America's Indo-Pacific allies to supply it.

The Pentagon defines naval expeditionary operations as those "mounted from the sea, usually on short notice, consisting of forward deployed, or rapidly deployable, self-sustaining naval forces tailored to achieve a clearly stated objective." The U.S. Navy currently deploys nine expeditionary strike groups.

Braithwaite, a former Navy pilot, said reactivating the 1st Fleet would involve a shift in naval forces. Many of the new fleet's ships and personnel will likely be taken from the 7th Fleet.

The 1st Fleet was decommissioned in 1973. Last month, he again called on the Navy to establish a new fleet closer to the border of the Indian and Pacific Oceans to combat the naval challenges posed by the People's Liberation Army Navy.

"We want to stand up a new numbered fleet," he said. "And we want to put that numbered fleet in the crossroads between the Indian and the Pacific Oceans.

"We can't just rely on the 7th Fleet in Japan. We have to look to our other allies and partners like Singapore, like India and actually put a numbered fleet where it would be extremely relevant if, God forbid, we were to ever to get in any kind of a dust up."