The barrage of medium-range missiles that North Korea fired into the ocean late Sunday night and early Monday morning actually included five missiles, not four, but one of the missiles failed at launch, according to two senior defense officials.

The four missiles traveled more than 600 miles east towards Japan before hitting the water.

Asked about the launch in Monday's daily gaggle, Pentagon spokesman Capt. Jeff Davis would say only that the U.S. tracked multiple launches and that four missiles "splashed down" in the sea. Davis characterized the overnight launch as "consistent with North Korea's long history of provocative behavior."