North Korea and the United Nations Command have started talking about the case of Travis King, the American soldier who entered the North last week, according to the deputy commander of the U.S.-led command in charge of overseeing the Korean War armistice.

On July 18, King, a U.S. Army private stationed in South Korea, ran across the Demilitarized Zone and entered nuclear-armed North Korea. This put Washington in a new diplomatic bind with the North.

Conversations between the UNC and North Korea’s military were initiated and conducted through a mechanism established under the Korean War armistice, according to Lieutenant General Andrew Harrison, a British Army officer serving as deputy commander of the multinational force.

“The primary concern for us is Private King’s welfare,” Harrison told a media briefing, declining to go into detail about the contact with the North.

“The conversation has commenced with the KPA through the mechanisms of the Armistice agreement,” Harrison said, referring to the North’s Korean People’s Army.

“I can’t say anything that could prejudice that process.”

North Korea’s state media, which has usually commented whenever U.S. nationals have been detained, has remained silent about King.

The incident comes at a time of heightened tension on the Korean peninsula. Last week, North Korea conducted ballistic missile tests hours after a U.S. nuclear-armed ballistic missile submarine arrived at a South Korean port.

It was the first such visit since the 1980s, and served a blunt reminder to the North that Washington always has nuclear-tipped missiles deployed within close striking distance.

North Korea is banned under U.N. Security Council resolutions from using ballistic missile technology, which Pyongyang defiantly rejects.

Tours to the border truce village, known formally as the Joint Security Area (JSA), were suspended after King bolted across the border.

People joining those tours, which are overseen by the UNC, need to sign up well in advance to get approval and are supposed to follow strict rules, including what they can wear, for the tour.

It remained a subject of an ongoing inquiry how King was authorized to go on the tour despite his record, Harrison said.

King had served detention in South Korea on charges of assault and damaging public property and was due to fly back to his home base in Fort Bliss, Texas last week to face disciplinary action.

When asked if the plan is to keep the area open to the public, Harrison said when or how the JSA part of these tours would resume was yet to be decided.

“It’s a constant balance between that value (of educating the public) and the risk to the individuals who are in the Demilitarised Zone,” he said.

On Saturday, the North fired a barrage of cruise missiles toward the sea to the west of the Korean Peninsula. On Monday, another U.S. nuclear-powered submarine arrived in South Korea.

Late last week, North Korea warned that deployment of U.S. aircraft carriers, bombers or missile submarines in South Korea could meet criteria for its use of nuclear weapons.