President Yoon Suk Yeol delivers a speech before some 400 US troops stationed at Camp H. M. Smith in Halawa, Hawaii, Tuesday. (Yonhap)

President Yoon Suk Yeol stressed the United States Indo-Pacific Command's role in taking the alliance between Seoul and Washington to a new level, amid growing geopolitical tensions beyond the Korean Peninsula.

Yoon on Tuesday local time visited the headquarters of the Indo-Pacific Command at Camp H. M. Smith in Halawa, Hawaii, near Honolulu. The last time a South Korean head of state visited the base was then-President Kim Young-sam 29 years ago.

"Among many other important missions, the Indo-Pacific Command supports ROK-US combined combat readiness and plays a central role in providing US augmentation in case of a contingency on the Korean Peninsula. It's indeed the central pillar of the ROK-US alliance," Yoon told some 400 US troops stationed in Honolulu, Hawaii, referring to South Korea as its official name, the Republic of Korea.

"Strong capabilities undergirded by rock-solid commitment and close cooperation are the true driving force defending the rules-based order and the region based on values and norms, and the US Indo-Pacific Command is at the very heart of this effort," he said in Korean with simultaneous English interpretation.

Yoon also pointed to growing geopolitical tensions on the Korean Peninsula, with speculation of military exchanges between North Korea and Russia, which the US and Ukraine say have allowed Russia to use North Korean ammunition and weapons in its war against Ukraine.

"I stand here amid a wave of global geopolitical situations and instability on the Korean Peninsula, because visiting no other place can better demonstrate and strengthen our ironclad alliance and robust combined defense posture than coming to the Indo-Pacific Command," Yoon said.

Yoon added that strength based on international solidarity is key to fighting "reckless actors."

"Last month, Pyongyang signed a treaty on a comprehensive strategic partnership with Moscow and pledged to strengthen their military and economic cooperation, raising the concerns of the international community," Yoon said.

"In order to defend our freedom and democracy and prosperity from those reckless actors, we need strength, and countries with shared common values must unite in solidarity."

President Yoon Suk Yeol (left) and first lady Kim Keon Hee (second from left) are seen boarding Air Force One as he flew from Hawaii to Washington on Tuesday. (Yonhap)

This came as Yoon was quoted as saying by the presidential office during his meeting with Adm. Samuel Paparo, commander of the US Indo-Pacific Command, that the combined defense readiness posture of South Korea and the United States is more important than ever amid North Korea's continued nuclear capability advancement and provocations.

Paparo, who Yoon awarded the Tongil Medal of the Order of National Security Merit on Tuesday, was quoted as saying by presidential office spokesperson Kim Soo-kyung that Yoon's decision to provide humanitarian aid to Ukraine "drew a clear insight that the security in Ukraine and the security in Indo-Pacific region are interconnected."

Spokesperson Kim also said that first lady Kim Keon Hee visited the Korean Christian Church founded in 1918 by Syngman Rhee in Honolulu. Kim thanked overseas Koreans in Hawaii for their contribution to the South Korea-US alliance, according to the presidential office.

In the afternoon, Yoon left for Washington to attend the North Atlantic Treaty Organization Summit later this week. The South Korean leader represents one of the four Indo-Pacific partners, along with Japan, Australia and New Zealand.