US Defense Secretary James Mattis at Korean DMZ: 'Our goal is not war'

Mattis spoke during a visit to the demilitarized zone (DMZ) that divides North and South Korea, which came after Pyongyang this week renewed its threat to test a nuclear weapon above ground.

"North Korean provocations continue to threaten regional and world peace and despite unanimous condemnation by the United Nations' Security Council they still proceed," Mattis said.

Facing away from North Korea, Mattis referenced the words of his colleague, US Secretary of State Rex Tillerson, saying that "our goal is not war, but rather the complete, verifiable and irreversible denuclearization of the Korean peninsula."

Music from both sides -- propaganda songs from the North, and K-pop from the South -- was audible as he spoke.

North Korea has been a particular thorn in the side of US President Donald Trump's administration, with the regime claiming advances in its nuclear weapon and missile program and its continued threats and provocations putting the US and its Asian allies on high alert.

DMZ tour; history lesson

Mattis visited Observation Post Ouellette at the heavily-guarded border, accompanied by US and South Korean Joint Security Area Commanders Lt. Col. Matthew Farmer and Lt. Col. Kwon Young-hwan, before moving to the Freedom House at Panjunmon Village, near the military line of demarcation which separates the two neighbors and rivals.

There he received a briefing from the South Korean Minister of Defense Song Young-moo, who led his counterpart through the history of the Korean War battles fought at the DMZ.

Mattis said that history "reminds us we fought together in very difficult times, and we will stick together today."

Song pointed out the North Korean units stationed north of the 38th parallel and said that he felt "a defensive operation" against the number of units was "unfeasible."

The DMZ is the de facto border between North and South Korea. It's four kilometers (2.5 miles) wide, stretches 250 kilometers (160 miles) and is dotted with military guard posts, mines and defensive structures.

It was established by the 1953 armistice agreement which ended the Korean War, though both sides technically remain at conflict as no peace treaty has ever been signed.

Asia tour

Earlier on Friday, Mattis visited two US military installations, Osan airbase and the Yongson garrison in Seoul.

The secretary had come to South Korea from Thailand, where he attended the funeral of former King Bhumibol Adulyadej.

Mattis' trip to the region comes ahead of US President Donald Trump's visit to Asia next week.

Trump will most likely forgo a visit to the heavily fortified border between North and South Korea when he visits Asia, a senior White House official said earlier this week, bypassing what has been a symbolic opportunity for US commanders-in-chief to stare into the Hermit Kingdom.

Citing scheduling conflicts in an already jammed itinerary, the official did not rule out entirely a visit to the demilitarized zone.

But, speaking to reporters, the official downplayed the importance of stopping at the DMZ, which the past three US presidents have visited during trips to South Korea.

US Vice President Mike Pence visited the DMZ in April, describing it as the "frontier of freedom."

Coming shortly after a failed North Korean missile test, Pence said at the time that the "era of strategic patience is over."