After North Korea launched an intercontinental ballistic (ICMB) missile on Thursday, the U.S. military and South Korean militaries will continue joint air force drills through this weekend.

South Korean media reported that officials believed the North’s ICBM crashed in flight, but didn’t elaborate. Two short-range ballistic missiles from North Korea fell into the ocean to its east. Japan raised alarms initially after tracking indicated that the ICBM would pass over Japan, but officials later claimed they lost track of the missile mid-flight according to Reuters.

According to Yonhap news agency, “North Korea’s ICBM Launch is Presumed to Have Ended in Failure”

ICBMs can travel almost anywhere on the planet to deliver a nuclear weapon.

On Wednesday, North Korea launched a record number of missiles. Meanwhile, the United States and South Korea flew hundreds to simulate military operations.

This was the North’s largest ever missile barrage, with only 16 miles from the South Korean border.

Since September, when the U.S. began joint military exercises with South Korea, North Korea has become more aggressive. In early October, the country flew 12 warplanes close to the South Korean border. Eight fighter jets and four bombardiers were involved in the sortie. South Korea responded by sending 30 warplanes. However, the two groups were not able to engage.

Operation Vigilant Storm is a joint U.S.-South Korean air force exercise. It was originally scheduled to end Friday, but it will continue into the weekend after North Korea launches.

This exercise involves allied fighter jets, bombers and bombers performing simulated attacks on South Korea 24 hours per day.

In October, South Korea launched a failed missile from its own launch. This occurred as Japan, the U.S. and South Korea were trying to send a message back to North Korea after the missile it had launched flew over Japan. Officials from the U.S. military clarified that while the missile’s warhead did not explode, the propellant did. It caused large explosions and flames.

The incident resulted in no injuries, either civilian or not, and officials from South Korea say that no buildings were damaged.