Human error led to a failed U.S. Navy ballistic missile intercept test, according to a report Monday.

A U.S. Missile Defense Agency investigation found a sailor on the destroyer John Paul Jones, the Navy's ballistic missile defense test ship, pressed the wrong button into the combat system, causing the missile to self-destruct before reaching its target.

Defense News reports the sailor, a tactical datalink controller, accidentally identified the incoming ballistic missile target as a "friendly in the system," causing the missile to combust.

The test, which occurred on June 22, was the fourth test of the missile defense system, which is known as SM-3 Block IIA.

The previous test in February was successful. The missile defense system is a joint project between the U.S. and Japan, meant to contest increasing missile threats from North Korea and others.