WASHINGTON -- US President Joe Biden congratulated South Korea's President-elect Yoon Suk-yeol on Wednesday, the White House said.

Biden and Yoon talked on the phone hours after the incoming South Korean leader was declared the winner in the South Korean presidential election.

"President Joseph R. Biden, Jr. spoke today with President-elect Yoon Suk-yeol of the Republic of Korea (ROK) to congratulate him on his election," the White House said in a press release, referring to South Korea by its official name.

"Together, they affirmed the strength of the US-ROK alliance, which is the linchpin for peace, security and prosperity in the Indo-Pacific," it added.

A White House spokesperson earlier said Biden looked forward to working with President-elect Yoon to further expand their countries' close cooperation.

Biden reaffirmed the US' commitment to the defense of South Korea, according to the White House.

"The two also committed to maintain close coordination on addressing the threats posed by the Democratic People's Republic of Korea's nuclear and missile programs," it said of his call with Yoon.

Biden was the first foreign leader to personally congratulate Yoon on his election, according to Yoon's aides.

Political watchers believe Biden may also become one of the first foreign leaders to hold a summit with Yoon as he is expected to take an Asia trip in late May for a Quad summit.

Yoon, a former prosecutor general, is set to take office on May 10. (Yonhap)