South Korea plans to sever an intelligence-sharing agreement with Japan amid a crisis between the two key U.S. allies.

Why it matters: The Trump administration had urged South Korea not to take this step, which could hamper communication over the threat from North Korea. It came after Japan elected to slow exports of sensitive materials to South Korea on national security grounds, a move that provoked outrage and boycotts in South Korea. The bitter feud is linked to colonial-era abuses by Japan and looks unlikely to be resolved soon.