Germany joined the U.S.-led United Nations Command (UNC) in South Korea, becoming the 18th nation in a group that helps police the heavily fortified border with North Korea and has committed to defend the South in the event of a war.

The move is evidence of Berlin's strong belief that European security is closely linked to security in the Indo-Pacific region, Defence Minister Boris Pistorius told a ceremony at the main U.S. military headquarters in Pyeongtaek, south of Seoul.

It is the latest move by the United States and its partners to expand alliances and partnerships, including those that span the globe, and try to turn the 74-year-old command into a source of broader regional security.