we're obviously in the early stages of assessing the incident. it's a tragedy, clearly, and the president was briefed immediately on -- and made aware of it immediately and briefed on it, and we're monitoring the situation. >> shepard: we're expecting a news conference. do we know if the marines have any clue what happened here? reporter: well, shep, it's not clear, but the 60-millimeter more tar being used in the activities, it exploded prematurely, we're told. five marines were killed instantly. one died awaiting med-evac. one died on route to the hospital. seven more were injured some were taken 140-miles to reno for treatment. the incident did not involve the ammunition depose -- depots. the marines were from camp he