"[The main challenge the navy faced] In a word, it is China," Gilday said in a presentation at the Heritage Foundation on Thursday. "We see a force that has tripled in size. We see a heavy investment in systems with long range. They are a significant adversary."
He described China's behavior in the Western Pacific as "fairly aggressive."
Current plans called for the US navy to reach a target size of 355 manned and 150 unmanned vessels by 2040, but Gilday warned that the navy had to be prepared to fight a war in the Pacific within five years from now.
"We have to be ready for the 2027 scenario [with China]," he said.
China remained the main threat that the navy had to face, Gilday reiterated.