President Joe Biden underscored the strength of the US relationship with South Korea during a call Saturday with Prime Minister Han Duck-soo, who became acting president after the impeachment of Yoon Suk Yeol.

"President Biden expressed his confidence that the Alliance will remain the linchpin for peace and prosperity in the Indo-Pacific region during Acting President Han`s tenure," the White House said in a readout of the call, reports AFP.

"President Biden expressed his appreciation for the resiliency of democracy and the rule of law in the Republic of Korea and reaffirmed the ironclad commitment of the United States to the people of the Republic of Korea."

South Korean lawmakers voted on Saturday to impeach Yoon over his brief declaration of martial law, which plunged the country into some of its worst political turmoil in decades.

Technocrat Han has stepped in as interim leader as a constitutional court deliberates over whether to permanently remove Yoon from office.