The United States will continue military exercises with Japan and South Korea as it sees the trilateral alliance vital for the stability in the Pacific challenged by North and China, US Secretary of Defence Mark Esper told reporters.

"Another American priority is the complete denuclearization of North Korea. The relationship among the United States, Japan and the Republic of Korea remains vital to addressing this challenge," Esper said on Tuesday, speaking at the Pentagon along with his Japanese counterpart Taro Kono. "We will continue trilateral defense exercises and information sharing to bolster regional security and achieve that objective."

He added that the United States sought to balance "constructive engagement" with China with the protection of American interests.

"We continue to counter China’s destabilizing behavior in the region, especially in the South and East Chinese Seas, and we remain opposed to unilateral attempts to undermine Japan’s administration of the Senkaku islands," Esper said.

The uninhabited archipelago, which China calls the Diaoyu Islands and Japan refers to as the Senkaku Islands, has a strategic importance for its location on shipping routes, fishing grounds, and and gas fields. Last June, both China and Japan deployed military vessels to patrol near the islands.

Meanwhile, in California US Secretary of State Mike Pompeo met on Tuesday with his Korean and Japanese counterparts Kang Kyung-wha and Toshimitsu Motegi.

According to the State Department spokesperson Morgan Ortagus, they emphasized the importance of the US-South Korea and US-Japan alliances to security and prosperity in the Indo-Pacific region and stressed that trilateral cooperation is essential for the future of peace in the region.