CNN CNN Newsroom March 19, 2013 18:05:00
Immediately and briefed on it and we're monitoring the situation. >> cnn's chris lawrence is live for us at the pentagon. chris, what more do you know, what caused the explosion? >> basically officials are telling us that this 60 millimeter mortar shell detonated in the tube at the firing point. in other words, instead of the mortar flying out, the mortar exploded right in the tube with the marines all gathered around it. normally it would take several marines a mortar crew so to speak to operate this, but this was training, so you may have had support personnel also around the mortar firing. ...