SEOUL, South Korea -- South Korea's Joint Chiefs of Staff said in a statement that North Korea attempted to launch an unidentified missile at about 5:20 a.m. local time but that it is presumed to have failed.
The JCS says it is further analyzing the situation, and gave no other immediate details.
The apparent launch failure comes amid tensions over recent nuclear and missile progress that has outsiders worried North Korea is closing in on its goal of a nuclear missile that can hit mainland America.
South Korea has also rejected recent North Korea overtures to talk, part of what some analysts see as an attempt to start dialogue meant to win the impoverished country aid.
Earlier this month a Seoul defense official said South Korea, the United States and Japan said they will hold their first joint military training next month focused on cooperating to detect signs of missile launches from North Korea and trace missile trajectories.
The drills, set for around June 28, will be held on the sidelines of biennial multinational naval exercises scheduled for waters off Hawaii from June to August, which the three countries regularly attend, the official said. The official spoke on condition of anonymity, citing department rules.
The trilateral drills will involve Aegis-equipped ships from the three countries, but they will not involve missile-interception training, the official said. The three countries have held joint search-and-rescue drills in the past.
The training follows a 2014 intelligence-gathering pact among the three countries, designed to better cope with North Korea's increasing nuclear and missile threats. It was the first such agreement among the three countries.
Washington regularly holds military drills with South Korea and Japan -- which together host about 80,000 American troops -- and shares intelligence with them on a bilateral level. But Seoul and Tokyo don't, largely a result of lingering public resentments in South Korea against Japan over its 1910-1945 colonial rule of the Korean Peninsula.
The Korean Peninsula was divided into a U.S.-backed South Korea and a Soviet-supported, socialist North Korea at the end of the Japanese occupation. The two Koreas fought a devastating three-year war in the early 1950s that ended with an armistice, not a peace treaty.