3 separate lights moving in formation/Changing formation.

I was running a tug boat heading east on the Neuse River approx 3 miles NE of Oriental, NC heading towards the Pamlico sound. I observed 3 white lights to my east in the sky in a triangle formation. The lights seemed to be moving to the SE. at times they would separate from each other briefly then come back together in a triangle formation. The movement I can describe only as unusual. The lights were white in color and dim brightness. I would guess they were at a distance of 8 to 10 miles and no higher than 5000 feet in altitude. After observing for approx 5 minutes they just disappeared. I see lots of lights and stuff running boats along the coast at night but this ranks with me as unusual.