WASHINGTON (AP) — The commander of U.S. forces in the Pacific has delivered some choice put-downs of China as tensions rise over Beijing's build-up in the disputed South China Sea.

While U.S. and Chinese diplomats tend to cushion their barbs over who is to blame for militarizing the region, there was little mistaking the meaning of Adm. Harry Harris, Jr., when he testified to Congress this week.

On Wednesday before a House panel, he described Chinese militarization as being "as certain as a traffic jam" in Washington D.C. On Tuesday, he told senators that to believe otherwise, "you have to believe in a flat Earth."

He has also dismissed as "tone deaf" the Chinese government official who had compared China's deployment of defense facilities on land features in the South China Sea to what the U.S. does in undisputed Hawaii.

China has reclaimed more than 3,000 acres of land and installed airstrips, radar and other facilities on land features in the South China Sea as it looks to assert what it contends is its historical right to sovereignty over most of those waters.

Five other Asian governments have territorial claims there.

Harris told lawmakers that China is changing the operational landscape of the South China Sea and seeks "hegemony" of East Asia.

He also said it was "preposterous" that China would try to "wedge itself" between South Korea and the U.S. to oppose the potential deployment of a defensive missile defense system against North Korea. Critics say the system's radar range could extend into China.

Harris' comments would have ruffled Chinese feathers, coming hours before Beijing's top diplomat met Tuesday with Secretary of State John Kerry in Washington, where the two sides publicly aired their differences, but it less stark terms.

Chinese Foreign Minister Wang Yi said Beijing had shown restraint in the South China Sea. He implied that other nations, including the United States, were to blame for militarization, but said both China and the U.S. hope to maintain peace and stability there.

Wang did not refer to Harris' comments, but in a possible sign of displeasure, the Chinese envoy cancelled a planned visit Tuesday to the Pentagon. Spokesman Peter Cook said that was due to an unspecified "schedule issue."