https://finance.yahoo.com/news/south-korea-simulates-attack-norths-nuke-test-051218278--politics.html

Chang Kyung-soo, an official with South Korea's Defense Ministry, told lawmakers that Seoul was seeing preparations in the North for an ICBM test but didn't provide details about how officials had reached that assessment. Chang also said the yield from the latest nuclear detonation appeared to be about 50 kilotons, which would mark a "significant increase" from North Korea's past nuclear tests.

In a series of tweets, President Donald Trump threatened to halt all trade with countries doing business with the North, a veiled warning to China, and faulted South Korea for what he called "talk of appeasement."