North Korea launched another ballistic missile off its east coast, but the test appeared to fail, South Korean officials said Friday. The failed launch coincided with the birthday of North Korea’s founding leader and Kim Jong Un’s grandfather, Kim Il Sung. The missile was likely a Musudan, an intermediate-range ballistic missile with a design range of more than 1,800 miles, South Korea’s Yonhap news agency reported, citing government sources. The U.S. said Thursday it was aware of reports that Pyongyang was preparing to test intermediate-range missiles and was closely monitoring the situation. The move follows North Korea’s fourth nuclear test in January and long-range rocket launch in February, which sparked a new round of tougher UN sanctions.