South Korean President Yoon Suk-yeol has reminded US lawmakers of the need to work together to safeguard peace, and he has thanked Americans for their defense of freedom.

Yoon made the remarks while addressing a joint session of Congress in Washington on Thursday.

Reflecting on the 70th anniversary of the bilateral alliance, Yoon thanked American veterans of the Korean War. He added that people in both countries need to protect democracy with their blood and sweat.

Yoon said, "Our alliance is stronger than ever, more prosperous together, and more connected, like no other. Indeed, it has been the linchpin safeguarding our freedom, peace and prosperity."

Yoon met with US President Joe Biden on Wednesday. The two leaders agreed that South Koreans will have a greater voice in the use of US nuclear weapons in any conflict on the peninsula.

In his address to lawmakers, Yoon reiterated that provocations from the North pose a serious threat. Still, he said promoting freedom for North Koreans is a "duty." He added that it is necessary to "speed up" trilateral cooperation with Japan to counter those threats.

Yoon surprised those invited to a state dinner on Wednesday by singing one of his favorite songs, "American Pie." He said it is no surprise to hear Korean and American singers rising up each other's music charts. He added that people in both countries are creating "new pattern of synergy."