Would that be the Marine Corps 155mm batteries, or did they pull out and get replaced by US Army assets?
Early rep[orts did not mention Marines specifically but ‘special forces’ personnel. Likely HIMARS and 155s, early reports also mentioned, in addition to the Apaches, Mr Spooky or Mr Spectre (AC-130U & H) ... he was likely too far away for the Russians to see, even so, without manpads and just assault rifles, there wad little the Russians could do against hm.