President Yoon Suk Yeol vowed Thursday to sternly respond to North Korea's nuclear and missile threats through a firm South Korea-US alliance, as he marked the anniversary of a key battle in the 1950-53 Korean War.

Yoon attended a ceremony commemorating the Battle of Jangjin Reservoir at the War Memorial of Korea in Seoul, along with some 2,800 Korean and American veterans, and military and government officials, including Veterans Minister Park Min-shik, Defense Minister Shin Won-sik and US Ambassador to Seoul Philip Goldberg.

During the two-week battle that started on Nov. 27, 1950, in South Hamgyong Province in the North, South Korean troops and the 1st Marine Division of the United States fought fiercely against Chinese forces, paving the way for the famous Hungnam evacuation, in which UN troops helped pluck some 100,000 Korean civilians out of harm's way.

"The South Korea-US alliance, which was forged in blood during the Korean War, has developed into the most successful alliance in the world over the last 70 years, and the South Korea-US alliance today is stronger than ever," Yoon said during remarks at the ceremony.

"Our government will respond sternly to North Korea's provocations, and nuclear and missile threats, which are becoming increasingly explicit, based on the firm South Korea-U.S. alliance," he said.

Yoon promised that the South Korean people and government will never forget the noble sacrifices of the heroes killed in the Battle of Jangjin Reservoir.

"Also, while strengthening security cooperation among South Korea, the US and Japan, and banding closely together with partner nations, we will contribute to freedom, peace and prosperity in the world," he said.

Yoon was the first sitting president to attend the annual commemoration ceremony for the Battle of Jangjin Reservoir, according to his office. This year also marks 70 years since the establishment of the South Korea-US alliance. (Yonhap)