SEOUL - South Korea's President Moon Jae-in said on Thursday that North Korea's latest missile launch was probably a subdued protest against the United States after a failed summit of the two countries' leaders in Hanoi in February.North Korea fired what appeared to be two short-range missiles on Thursday, according to South Korea's military, days after its leader Kim Jong Un oversaw the test of multiple rockets and a missile."North Korea seemed to be discontented it could not reach a deal in Hanoi," Moon said in an interview with South Korean broadcaster KBS.But the North appeared to have refrained from using weapons that directly threaten the United States, Moon said.