U.S. Secretary of Defense Pete Hegseth speaks to the media after welcoming U.K. Secretary of State for Defense John Healey to the Pentagon in Arlington, Va., March 6. EPA-Yonhap

The Pentagon on Friday reaffirmed America's "ironclad" commitment to the South Korea-U.S. alliance and vowed to maintain the "fight tonight" readiness posture with the Asian ally, after Seoul was excluded from Defense Secretary Pete Hegseth's upcoming trip to the Indo-Pacific.

The decision to exclude South Korea from the Pentagon chief's first Asia swing since taking office in January came amid lingering speculation that a period of political uncertainty, caused by President Yoon Suk Yeol's impeachment over his martial law attempt in December, would have a negative impact on the allies' security cooperation.

"While we have no travel details to announce today, our ironclad commitment to the alliance remains clear," Pentagon Press Secretary John Ullyot said in response to a request for comment by Yonhap News Agency.

He suggested that security cooperation between Seoul and Washington continues unimpeded.

"Freedom Shield 25 is currently underway, and it strengthens the role of the alliance as the linchpin of regional peace and security. The USS Carl Vinson also visited the peninsula this month and conducted operations with ROK forces," referring to the allies' ongoing annual military exercise. ROK is short of South Korea's official name, the Republic of Korea.

"We will continue to maintain a 'fight tonight' readiness posture with our ROK allies," he said.

Hegseth is said to be planning to visit Hawaii, Guam, Japan and the Philippines in what would be a high-profile trip to underscore the Trump administration's commitment to the Indo-Pacific in the face of China's growing assertiveness and North Korea's recalcitrance.

Even though his visit to Korea is excluded this time, observers anticipated the Pentagon chief could weigh a visit to Seoul on other future occasions, including the annual Shangri-La Dialogue in Singapore or the annual South Korea-U.S. Security Consultative Meeting set to be held in Seoul this year.

Last month, Hegseth was first reported to be considering visiting South Korea after the allies' annual Freedom Shield exercise concluded this month. If realized, his trip was expected to be the first visit here by a Cabinet-level Trump administration official since Trump took office in January.

The report on Hegseth's potential visit gave rise to speculation that he could visit a South Korean shipbuilding company given that Trump has expressed his interest in cooperating with South Korea, a treaty ally, to help rebuild America's shipbuilding industry.

Amid the political turmoil triggered by Yoon's short-lived martial law imposition Dec. 3, then Defense Secretary Lloyd Austin canceled the Korea portion of his Asia trip later that month. (Yonhap)