The U.S. military and intelligence community is still analyzing data from the test launch to determine what type of missile was fired and how far it went.
It is not yet known whether the missiles were short, medium or long-range, like an intercontinental ballistic missile (ICBM).
The United States tracks all North Korean weapons tests using radar and satellites. US satellites are able to detect heat signatures from a missile launch almost immediately.
Earlier in the day, the South Korean Joint Chiefs told reporters that North Korea had launched an unidentified projectile towards the sea between the Korean peninsula and Japan.
The Japanese Coast Guard warned ships to be on the lookout for falling wreckage.