Reuters reports the launch was made from “near the city of Wonsan, on North Korea’s east coast, the same place from where it launched several intermediate-range missiles last year, all but one of which failed.”

A South Korean military official agreed with the U.S. assessment that the missile “may have exploded right after it took off from a launch pad.”

The Washington Post writes that American and South Korean military intelligence services are still analyzing the data they gathered about the launch and are not yet certain precisely what type of missile it was. 'US Pacific Command detected what we assess was a failed North Korean missile launch attempt ... in the vicinity of Kalma,' Commander Dave Benham, a spokesman for US Pacific Command, said in a statement, referring to an air field on North Korea's east coast. “A missile appears to have exploded within seconds of launch,” Benham said, adding that work was being carried out on a more detailed assessment. South Korea's Yonhap news agency said the missile may have exploded as it was launched, before reaching an altitude at which it could be detected by South Korean radar. “The nuclear force of [North Korea] is the treasured sword of justice and the most reliable war deterrence.”

South Korea also confirmed the failed launch and said it was analyzing what type of missile was fired, a South Korean military official confirmed to NBC News. Also Wednesday, a U.S. Air Force B-1B bomber and South Korean fighter jets conducted joint training exercises that displayed "strong deterrence against North Korean nuclear and missile threats," South Korea's Defense Ministry said. We continue to monitor North Korea’s actions closely.”

The launch comes a day after the North issued an ominous warning of a potential pre-emptive strike after a test over the weekend of a new advanced rocket engine. During his trip to Asia last week, U.S. Secretary of State Rex Tillerson warned the United States would consider preemptive strikes against North Korea if Pyongyang’s threat to Washington and its Asian allies grew too big. North Korea conducted two nuclear test explosions and 24 ballistic missile tests during 2016, and experts say it could have a nuclear-tipped missile capable of reaching the U.S. mainland within a few years.
According to South Korean and United States officials, a missile test in North Korea ends in failure, with the missile exploding seconds after launch.