Four years ago, three aircraft carriers, including the Reagan, arrived in South Korea for naval exercises with South Korea in response to North Korea's nuclear and missile tests.

Its arrival marks the most significant deployment yet under a new push to have more U.S. "strategic assets" operate in the area to deter North Korea.
Diplomats have reiterated the US's commitment to defend South Korea in the event of a nuclear war.

North Korea has dialed up weapons testing to a record pace in 2022, launching more than 30 ballistic weapons including its intercontinental ballistic missiles since 2017, as it exploits a divide in the U.N. Security Council deepened over Russia's war on Ukraine.

North Korea has so far rejected the U.S. and South Korean calls to return to nuclear diplomacy, which has been stalled since 2019 over disagreements in exchanging the release of U.S.-led sanctions against the North and the North's disarmament steps.