The United States' alliances with South Korea and others are key to dealing with many challenges facing the US, including Chinese aggression and North Korean threats, nominees for US ambassadors to Japan and China said Wednesday.

Richard Nicholas Burns, nominee for US ambassador to China, said US alliances provided a "comparative advantage" over China.

"The comparative advantage that we have versus China is that we have treaty allies. We have partners who deeply believe in us and the Chinese really do not," the former under secretary of state for political affairs said in his confirmation hearing before the Senate foreign relations committee.

"And so in the Indo-Pacific, I think President (Joe) Biden has tried to emphasize the need for us to be very closely aligned with Japan, with South Korea, with Australia, our treaty allies, (and) our defense partners, the Philippines and Thailand," he added.

His remarks come amid growing competition and contention between the United States and China, while many observers also point to the increasing potential of direct confrontation over Taiwan.

Burns said the US must continue to advance its partnerships and alliances in the Indo-Pacific region such as the quadrilateral security initiative, known as the Quad, between Australia, India, Japan and the US

The US has also recently launched a new trilateral security initiative with Australia and Britain that seeks to deliver nuclear-powered submarines to Australia in what many view as an effort to counter China's growing military presence in the East China Sea and the South China Sea.

"What distinguishes us and strengthens us is the fact that we have our alliance with Japan, and our alliance with Australia and South Korea," said Burns.

Rahm Emanuel, nominee for US ambassador to Japan, echoed the sentiment, while also stressing the importance of cooperation between key US allies -- South Korea and Japan --- to counter threats posed by North Korea.

"This is a serious challenges related to security, and is security related to both South Korea and Japan," the nominee told the confirmation hearing when asked about North Korea's recent missile tests and what he would do, if confirmed, to help promote cooperation between Seoul and Tokyo.

North Korea has staged at least eight known missile tests this year, with Pyongyang test launching what it announced was a new submarine-launched ballistic missile (SLBM) earlier this week.

Emanuel said the SLBM test showed the threat posed by North Korea is not "theoretical."

"That to me underscores the level of urgency for all parties to now find the common ground, focus on the future, focus on what binds us together and not allow tensions of the past and disagreements to actually, in any way. endanger, and I do think (they) endanger the relationship," he added.

South Korea-Japan relations have been at their lowest ebb since mid-2019 when Tokyo took economic measures believed to be aimed at retaliating against a Seoul court decision that ordered Japanese firms to pay compensation to South Korean workers forced into free labor during Japan's 1910-45 colonial rule of Korea.

The former mayor of Chicago said the history issues between South Korea and Japan were "serious" and "heartfelt" issues, but insisted the countries must focus on areas they can work together.

"You never want the 20th century to rob us of the opportunities of the 21st century, not that those (history issues) aren't heartfelt and serious, and they are. So is the one keeping people focused on the future and our commonality, not what divides us," said Emanuel.

He underlined a need to keep history-related conversations between Seoul and Tokyo moving forward but privately, while focusing on new opportunities that can bring them together, such as North Korea and climate change.

"You don't want to embarrass or shame any one of the two parties publicly. So the goal would be to keep the private conversations moving forward, So there's no sense in a public way that they ... for their own respective roles and responsibilities to their publics, are not cornered from the opportunity to make the most of the 21st century." (Yonhap)