New Delhi, Nov. 18 -- The top U.S. admiral on Monday called China 's shipbuilding capability "impressive" as Beijing moves ahead with a rapid buildup of the world's largest navy, and said America's cooperation with Asian allies South Korea and Japan is essential for its own shipbuilding capability.

"How they utilize those aircraft carriers globally is, of course, a concern of mine," Adm. Daryl Caudle said in Japan, part of his 10-day tour of the Asia-Pacific.

China on Nov. 7 commissioned its latest aircraft carrier, Fujian, and began sea trials of its most advanced amphibious assault ship a week. China's navy already has more ships than the U.S. Navy, but it has fewer aircraft carriers, amphibious assault ships and other key vessels.

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