During middle of december 1968 while stationed on lz west, during an enemy attempt at breaching the perimeter, one of my soldiers came running up to my bunker yelling, "they're here. they're here." thinking the enemy breached the perimeter, i asked him where. he pointed straight up into the sky. i said what the hell are you talking about. he said "the ufo's". i told him he'd better get back to his bunker before i did something nasty to him. after the battle ceased, i spoke with him about the ufo's. he said he'd seen them before. i let it drop. on 20 december 1968, we were up in antenna valley. my unit was b co., 4/31st inf. i was the 3rd platoon leader. we moved up on top of a hill just before dark at which time i observed an enemy soldier running through an opening several hundred yards away. my platoon was responsible for the north side of the hill perimeter. sometime after dark, a couple of my positions reported movement coming up the hill towards them. i had them throw some grenades. the movement continued, so i called in some artillery. movement continued, so i called in more artillery, along with some helicopter gunships and eventually spooky. while in the process of coordinating all the supporting fires, the same young man crawled up to my position and indicated there was a ufo just to our west. i was able to locate what he had indicated, and it appeared to be bigger and brighter that the other stars in the sky. during one point when there was a lull in the supporting fires, i happened to look up at the star, just in time to see the star recede straight up into the sky so that it was the same size and intensity as the rest of the nearby stars. when the next round of supporting fires started, i observed the star descend to it's previous position and it remained there during the supporting fires. this went on all night. when there was ground fire, the ufo would descend and when the ground fire stopped, it would recede. during this whole time the ufo remained in it's approximate relative position with regards to the stars around it. if i didn't know where to look, i wouldn't have been able to see it. finally with daybreak approaching, the last aircraft was leaving on it's way to danang. i observed ufo at this point through my 7 x 50 binoculars. the ufo came much closer and began to circle to the south. it was at this point that the ufo was joined by two other ufo's that i had never noticed. through my binoculars while looking at the ufo i could see that what appeared to be a single point of light with the naked eye, was actually 5 windows. i could clearly see the 5 windows but nothing inside. all three ufo's continued to make a complete circle around our position, and when they reached the spot to the west where i had been observing the first ufo, they all three shot straight up into the sky and were gone in a fraction of a second.