In some of the images we appear to be looking at flares, in others, drones. I feel comfortable saying the light source is pyrotechnic based on classic burn in/burn out images.
What's unclear to me is the article statement the lights hovered in sight for two hours. I don't know if that means the exact same lights stayed visible for two hours, or if a series of lights were visible for two hours.
Airdropped battlefield illumination flares burn for 2-3 minutes under parachutes, airdropped infrared decoy flares maybe 10 seconds. If the witnesses saw a series of lights burning in/burning out over a two hour period, I'd put my money on flares. If they saw the exact same lights burn for two hours straight, it's almost certainly not flares.