Defense Secretary Mark Esper on Wednesday called out North Korea, saying Pyongyang’s military capabilities pose a “serious threat” to international security. 

“We agree that North Korea’s nuclear and ballistic missile programs remain a serious threat to the security and stability of the region and the world,” Esper said at the Pentagon during a meeting with South Korean Defense Minister Suh Wook.

“The United States remains committed to the security of the Republic of Korea,” Esper added. 

On Saturday, North Korean leader Kim Jong Un unveiled a new “monster” intercontinental ballistic missile during a military parade. Kim has previously said he would reveal a “strategic weapon” amid stalled nuclear negotiations with the U.S. 

In August, Esper advocated for diplomacy with North Korea while stating that the U.S. military has a responsibility to maintain a state of readiness.

North Korean denuclearization has been a major objective of the Trump administration. The White House has pushed for Pyongyang to pursue a path to denuclearization, in exchange for lifting economic sanctions.

U.S. and North Korean negotiators previously met in October 2019 in Sweden to discuss a nuclear deal, but talks fell through on the first day of discussions. According to the Stockholm International Peace Research Institute, North Korea added 10 nuclear warheads to its arsenal in 2019 alone.

Trump has promised to reach a nuclear deal with Kim “very quickly” if he wins a second term in November. In a departure from past administrations, Trump and Kim have met in person, though no deals were struck. 

Should Joe Biden win the upcoming election, the U.S. would likely revert back to Obama-era policies with North Korea. A Biden administration would push for North Korean denuclearization and negotiations with Kim would require preconditions.