I was out the back yard with my dog when two UFOs appeared. They hovered over the oil refinery for approx 30 minutes then vanished. One UFO was large and had a weird shape to it and the 2nd smaller UFO was like a saucer with flashing lights. The larger UFO has pulsating red, blue, green and white lights. It made no noise. It could not have been a helicopter as it was too big. They just hovered typewritten gone. It was strange. I didn't feel frightened was curious as I watched a satellite's over and a plane fly above the UFO and it never moved. The larger UFO was like a straight line of lights across with a line of lights going downwards and a line going above but not like a cross.UFO Sightings occurred over Pembrokeshire GB on March.23,2017 mufon cms# 83048