SEOUL, South Korea (AP) — North Korea says a recent launch of ballistic missiles was meant to send a warning to the Washington and Seoul over their ongoing joint military exercises. North Korea has conducted four rounds of weapons tests in two weeks, with state media saying the most recent Tuesday were supervised by leader Kim Jong Un. The launches come amid a stalemate in nuclear negotiations with the U.S. Though the tests are prohibited by the U.N., U.S. President Donald Trump has dismissed their significance.