WASHINGTON — U.S. President Donald Trump's order to reduce South Korea-U.S. military exercises is raising both hopes and concerns, as it could help ease tensions with North Korea but affect the allies' defense readiness amid Pyongyang's growing nuclear and missile threats. In a social media post on Sunday, Trump said he has instructed Defense Secretary Pete Hegseth to "substantially" scale back exercises with the Asian ally, noting that the drills are not only "costly" but also send a "totally inappropriate and hostile" signal to the North. The post came just as South Korea and the United States kicked off their annual Ulchi Freedom Shield (UFS) exercise intended to strengthen the allies' capabilities against potential North Korean aggression and test Seoul's ability to lead combined forces in a process to retake wartime operational control from Washington. Trump's directive raised cautious optimism for a resumption of diplomacy with North Korean leader Kim Jong-un. But questions arose over whether it could hurt the allies' efforts to counter the North's advancing military threats, as