President Moon Jae-in said Sunday he will "work together" with his US counterpart Donald Trump to boost the two countries' alliance and resolve North Korea's growing threats, at the upcoming summit meeting set to take place in Washington.

Marking the 67th anniversary of the outbreak of the Korean War, Moon wrote in a Facebook post that he will make every effort possible to secure national security based on strong defense capabilities. The two Koreas are technically still at war after the 1950-53 war ended in a truce, not a peace treaty.

"I will seek to strengthen the alliance between South Korea and the United States in talks with the US president and try to resolve the North's nuclear issue," he said in the post.

The new South Korean president is set to meet his US counterpart for two-day talks in Washington on Thursday and Friday (US time). It will be Moon's first-ever summit with a foreign leader since taking office on May 10. (Yonhap)