"America is committed to sustaining robust, ready and credible deterrence in the Indo Pacific, including across the Taiwan Strait," Hegseth said in Japan after talks with counterpart Gen Nakatani.

"Japan would be on the front lines of any contingency we might face in the western Pacific and we stand together in support of each other.

"That's why today Minister Nakatani and I talked about the severe and urgent security environment around Japan, and we discussed what we are going to do about it," Hegseth told reporters.

Beijing has stepped up military pressure in recent years around Taiwan, including near-daily air incursions, and has not ruled out using force to bring the island under its control.

"Today's meetings have affirmed the extraordinary strength of America's alliance with Japan. After today's discussion, it is clear to me that our alliance is the cornerstone of peace and security in the Indo Pacific negotiation," Hegseth said.

"America and Japan stand firmly together in the face of aggressive and coercive actions by the Communist Chinese."