Defense Secretary Jim Mattis on Friday warned North Korea that any use of nuclear weapons by Pyongyang would be met with an "effective and overwhelming" response.
Mattis delivered the stern remarks alongside his South Korean counterpart on his first trip as defense secretary, during which he assured Seoul of the United States' commitment to defending its allies in the Asia-Pacific.
"North Korea continues to launch missiles, develop its nuclear weapons program, and engage in threatening rhetoric and behavior," Mattis said alongside South Korean Defense Minister Han Min Koo on Friday in South Korea, according to remarks reported by the Associated Press.
"We stand with our peace-loving Republic of Korea ally to maintain stability on the peninsula and in the region," Mattis continued. "America's commitments to defending our allies and to upholding our extended deterrence guarantees remain ironclad: Any attack on the United States, or our allies, will be defeated, and any use of nuclear weapons would be met with a response that would be effective and overwhelming."
North Korea has pressed on with its nuclear and missile programs in defiance of international sanctions and condemnation. Kim Jong Un's regime conducted more than 20 missile launches and two nuclear tests in 2016, raising its total nuclear tests to five. Following one of the tests, North Korea claimed to have successfully detonated a nuclear warhead that could be mounted on a ballistic missile.
Han expressed similar concerns about North Korea's nuclear and missile programs on Friday, which he said threaten the international community and have resulted in a "severe security situation" on the Korean peninsula.
The United States is planning to deploy the Terminal High Altitude Area Defense, or THAAD, missile defense system to South Korea to safeguard from threats from the North, though it has been shrouded in doubt given approaching elections in South Korea.
Mattis discuss the schedule of the planned deployment with South Korean officials during his trip, describing the advanced missile defense system during his remarks Friday as one "defensive step" the U.S. is taking to respond to "threatening rhetoric and destabilizing behavior" from North Korea.
During a meeting with South Korea's Acting President and Prime Minister Hwang Kyo-Ahn and national security adviser Kim Kwan-Jin, Mattis underscored the Trump administration's commitment to the Asia-Pacific and strengthening the alliance between the U.S. and South Korea.
"During the meetings, the secretary emphasized the priority that President Trump places on the Asia-Pacific, and on strengthening the U.S.-ROK alliance. He also underscored that the United States remains steadfast in its commitment to defend the ROK and that the U.S. extended deterrence commitment remains ironclad," Cmdr. Gary Ross, a spokesman for Mattis, said in a readout of his meetings.
"Both ROK officials impressed upon Secretary Mattis the importance of close cooperation in the face of a growing North Korea nuclear and ballistic missile threat," Ross said. "The secretary responded that the alliance would continue to take defensive measures in response to this threat developments, such as the stationing of THAAD to Korean Peninsula."
Mattis, who was sworn in as defense secretary the day of President Trump's inauguration, is also visiting Japan on the second leg of his trip to the Asia-Pacific.