Adm. John Richardson before a meeting with Prime Minister Shinzo Abe in Tokyo. Thomson Reuters SINGAPORE (Reuters) - The U.S. navy needs to expand its fleet and maritime capability to remain competitive as other nations such as China and Russia seek to strengthen their naval power, Chief of Naval Operations Admiral John Richardson said on Tuesday.

"We are getting back into, after decades really, an era of maritime competition," Richardson told reporters on the pier alongside the USS Coronado at the Changi naval base.

"Some of these global powers, China, Russia, they've been growing, China in particular. They're maturing in every dimension of power (and) at some point you turn to the sea to expand and continue to prosper."

China last month launched its first domestically build aircraft carrier amid rising tension over North Korea, and worries about Beijing's assertiveness in the South China Sea and its broader military modernization program.

China's claims to the South China Sea, through which about $5 trillion in sea-borne trade passes every year, are challenged by Brunei, Malaysia, the Philippines, Vietnam, and Taiwan.

Richardson's comments come ahead of the release of the Future Navy White Paper on Wednesday at 1200 GMT (8.00 p.m. ET).

USS John C. Stennis conducts flight operations. U.S. Navy photo by Mass Communication Specialist Seaman Matthew Martino/Released

"Those who are challenging our interests are advancing at rates that are much faster than ours. To remain competitive, we must act now — we need a larger, better fleet in the 2020s, not the 2040s," said a Navy source familiar with the White Paper.

U.S. President Donald Trump has been seeking what he calls a "historic" increase in defense spending, but has run into opposition in Congress.

This month he scored a partial win, getting a commitment for up to $15 billion in additional funding for a military buildup - about half of what he originally asked for.

Richardson told Reuters in December that the U.S. arms industry was ready and capable of boosting production of new ships if Trump, then president-elect, made good his campaign vow to expand the navy to 350 ships from about 290.

"It's not just about numbers and platforms. It's also about what those platforms can do and then again how they all work together," said Richardson.

Richardson said there were plans to transition to more modern frigates in the near future. Earlier in May, it was reported the U.S. Navy had decided to delay by a year until fiscal 2020 the awarding of a design and construction contract for a planned new frigate.

(Reporting by Himani Sarkar; editing by Michael Perry)