CAMP BONIFAS, South Korea (AP) — U.S. Secretary of State Rex Tillerson visited the world’s most heavily armed border, greeting U.S. soldiers on guard near the tense buffer zone between rivals North and South Korea.

Tillerson touched down by helicopter Friday at Camp Bonifas, a U.S. base about 400 meters (438 yards) from the Demilitarized Zone, a Cold War vestige created after the Korean War ended in 1953. He planned to then move to the truce village of Panmunjom inside the DMZ, a cluster of blue huts where the Korean War armistice was signed.

Tillerson is the latest in a parade of senior U.S. officials to have their photos taken at the border. But it’s the first trip by the new Trump administration’s senior diplomat as he makes a tour of Japan, South Korea and China.

Speaking in Tokyo, Tillerson earlier vowed a tougher strategy to confront North Korea’s nuclear threat. But he offered no details about what would comprise the “different approach” to North Korea the U.S. will pursue. He pointedly noted that 20 years of “diplomatic and other efforts” had failed to dissuade the isolated communist government from developing its nuclear program.