PEARL HARBOR, Hawaii — A day after China laid out its vision for a navy that can project power into the open seas, Defense Secretary Ashton B. Carter on Wednesday criticized Beijing’s efforts to build artificial islands in the South China Sea, making it clear that the United States would not be deterred by Chinese claims to newly built territories.

Though American officials have long insisted that the Obama administration’s so-called pivot or rebalance toward Asia is not aimed at one country, Mr. Carter’s comments left little doubt that Washington shared the concerns of other Asian nations about China’s growing military presence in disputed areas of the South China Sea, and the increasingly assertive posture of its forces in disputed waters around Asia.

The South China Sea is especially sensitive. It is bisected by vital shipping lanes that connect Asia to the Middle East and Europe, and China’s efforts to create artificial islands and build military structures on reefs and other outcroppings have alarmed the Philippines, a close American ally, and other countries, like Vietnam and Malaysia.

“China’s actions are bringing countries in the region together in new ways. And they’re increasing demand for American engagement,” Mr. Carter said during a ceremony at the naval base at Pearl Harbor marking a change of command of United States forces in the Pacific. “We’re going to meet it. We will remain the principal security power in the Asia-Pacific for decades to come.”