TOKYO: US Vice President Kamala Harris was headed to Seoul and the Demilitarized Zone (DMZ) separating the Koreas on Thursday, just hours after North Korea test-fired missiles and underscored ongoing regional tensions.

Aides said the visit is intended to show unwavering US commitment to South Korea's security but took on new urgency after the two short-range ballistic missiles were shot off North Korea's east coast on Wednesday.

US President Joe Biden's aides have been shoring up alliances to manage China in the region, including over Taiwan. But South Korean President Yoon Suk-yeol told CNN in an interview aired on Sunday that in a conflict over Taiwan, North Korea would be more likely to stage a provocation and that the alliance should focus on that concern first.

The missile test is the second since Sunday and comes two days after South Korea and US forces conducted a military drill in waters off South Korea's east coast involving an aircraft carrier.

North Korea's Kim Jong Un has said it is developing nuclear weapons and missiles to defend against US threats.

North Korea fires two ballistic missiles ahead of Harris’ visit to South

Following a stop at a military base in Japan, Harris called recent missile launches part of an "illicit weapons programme which threatens regional stability and violates multiple U.N. Security Council resolutions."

Harris' visit to the DMZ is the first by a senior Biden administration official and is expected to follow a meeting with Yoon.

Several former US presidents, and Biden himself before he became president, have visited the DMZ, but former President Donald Trump became the first to have met a North Korean leader there when he held a third meeting with Kim Jong Un in 2019 as part of his unsuccessful effort to persuade Kim to give up his nuclear and missile programs.

The DMZ is often described as the world's last Cold War frontier and has existed since the 1950-53 Korean War ended in a armistice rather than a peace treaty.