Peering over the deck of a nuclear-powered aircraft carrier sailing through a disputed part of the South China Sea, U.S. Navy Rear Adm. George Wikoff said he's been impressed with the professionalism of China's navy.

"They remain respectful in accordance with what we anticipate a professional would do, and we respond or initiate in kind when we believe that there is a situation," said Wikoff aboard the Yokosuka, Kanagawa Prefecture-based USS Ronald Reagan last week, after taking over command of Task Force 70 two weeks ago. "It has been very cordial, and I think they have been very professional is really what I'd like to emphasize on both sides."

Sailing within waters China claims in its so-called nine-dash line off the coast of Malaysia, the $4.5 billion supercarrier was accompanied by one destroyer and two cruisers. It was headed for Singapore as part of freedom of navigation exercises meant to counter China's growing military presence in the region at a time when both countries are embroiled in a global trade war.