President Trump used Twitter Friday morning to warn that the U.S. is ready to go to war with North Korea. “Military solutions are now fully in place, locked and loaded, should North Korea act unwisely,” he wrote. “Hopefully Kim Jong Un will find another path!” Meanwhile, the United States and South Korea are preparing to stage a 10-day joint military exercise involving tens of thousands of troops on land, sea, and air. The drill comes as North Korea has threatened to fire missiles at Guam. The exercises, called Ulchi-Freedom Guardian, were long-planned for the end of the month and will run Aug. 21-31. Pyongyang has said it will be ready to fire four of its Hwasong-12 intermediate-range ballistic missiles at the U.S. Pacific island at that time.