Story highlights South Korean military and U.S. officials say two missiles launched

The launch comes while South Korea and the United States are involved in joint military exercises

(CNN) North Korea has launched two ballistic missiles off the west coast of the Korean peninsula, the South Korean military and U.S. defense officials said Friday.

The South Korean Joint Chiefs of Staff said that one ballistic missile flew a distance of 800 kilometers overland toward the sea off the country's east coast, while a second projectile, assumed to be a missile, was detected by radar but disappeared at an altitude of about 17 kilometers.

The military said it was closely tracking and monitoring the situation and maintaining a readiness posture for any North Korean provocation.

U.S. official confirmed the launch, with a U.S. defense official telling CNN that it tracked two ballistic missiles.

The launch came around 5:55 a.m. local time, near Sukchon county, South Pyongan province, the Joint Chiefs of Staff said.