President Yoon Suk Yeol visited the Pentagon on Thursday after adopting the Washington Declaration the day before in an apparent move to underscore the solid South Korea-U.S. combined defense readiness.

In receiving a security briefing from top U.S. military officials during the visit, Yoon stressed that he and U.S. President Joe Biden had agreed to further strengthen extended deterrence to better respond to North Korea’s nuclear and missile threats during their summit on Wednesday.

Yoon went on to say that he fully trusts the U.S.’ commitment to extended deterrence.

He said that an attempt by the North to use nuclear weapons would be met with a resolute response from the South Korean military and the South Korea-U.S. alliance, which includes the U.S.’ nuclear capacity.

Yoon then called on Pyongyang to realize that it has nothing to gain from nuclear weapons and opt for denuclearization for the sake of true peace and joint prosperity on the Korean Peninsula.

U.S. Defense Secretary Lloyd Austin said for the past seven decades, the South Korea-U.S. alliance has advanced to the most solid, capable and interoperable alliance that has been able to repress key disputes and attacks on the peninsula.

He added that extended deterrence includes all of the U.S. capabilities, including conventional nuclear weapons and missile defense capabilities.