A police helicopter crew has spotted what is described as an unusual aircraft in the Vale of Glamorgan. The helicopter was above St Athan, which is home to an RAF base and close to Cardiff International Airport
South Wales Police said the helicopter did not give chase and described the crew as very experienced.
"In today's skies, there are a wide variety of aircrafts which come in a range of different shapes and sizes and in all probability, this sighting has just confirmed that one of these was in the area at the relevant time," the spokesperson added.
A Ministry of Defence spokesperson said it had heard nothing about the incident.
"But it is certainly not advisable for police helicopters to go chasing what they think are UFOs," the spokesperson said.
Cardiff International Airport said air traffic control provided a service to the police helicopter to ensure it had appropriate air space, including allowing it space to return to RAF St Athan to refuel.
Breaking News: Wedding couple sparked UFO alert:
Could this be what the experienced police officers witnnessed!!!!!
Guests at the wedding made a wish before each glow lantern was lit
Special glow lanterns set off at a wedding could have been mistaken for a UFO by police officers in a helicopter.
The three-man crew spotted an unusual object in the sky above St Athan on 8 June in the Vale of Glamorgan.
It made headlines around the world but it was only when newlyweds Lucy and Lyn Thomas saw reports on honeymoon that they realised what could have happened.
The lanterns were lit in Cowbridge and floated off towards St Athan, close to an RAF base and Cardiff airport.
"There's no doubt in my mind it was our lanterns," said Mr Thomas, 30, a salesman from Llantwit Major in the Vale of Glamorgan.
"We went on the internet on our honeymoon in Turkey and saw a report about this UFO. I thought, 'oh no, it was exactly the same time and I remember they were going straight towards St Athan way'."
He said he could not believe the coverage the UFO sighting had had in the media.
You can't judge their size [in the air] because they're so bright. They just look like a big ball of light. When you light them they just go up and up and up
Lyn Thomas on the glow lanterns
The couple first saw the glow lanterns at the Glastonbury festival last year and thought they would make an ideal alternative to fireworks for their "mini festival" wedding party for 150 guests in a field near Cowbridge.
Mr Thomas bought 100 lanterns on an internet auction site and set off about 30 - with guests making wishes - from about 2300 GMT on 7 June until 0200 GMT on 8 June.
"I can see how they'd look like UFOs. They are about 2ft 6in (0.79m) high and are paper lanterns with a wax ball underneath.
"You light them and they inflate and float off - exactly the same principal as a hot air balloon," said Mr Thomas, who said he checked aviation regulations and made sure the lanterns were set off five miles away from Cardiff International Airport.
"You can't judge their size [in the air] because they're so bright. They just look like a big ball of light. When you light them they just go up and up and up.
"Strangely enough we saw them in Glastonbury last year and sat there for hours trying to work out what they were."
Once lit, some of the glow lanterns floated off towards St Athan
"It's just gone mad," he added.
"But everyone we've spoken to since said there's no doubt that they [the lanterns] were what they spotted."
Wedding guest Geraint James, from Llantwit Major, said he did not think about the connection between the lanterns and the UFO sightings until his newlywed friends rang him on Tuesday after returning from their honeymoon.
"They rang me and said 'do you realise that was probably us?' It was the exact time we set them off," he said.
"A few people had said they looked like UFOs, kind of spooky as they floated off.
"I read about the UFO on the BBC website and saw it had had coverage in India and in the New York Times. It made us laugh. I suppose this sheds a bit of light."
The police helicopter crew reported seeing the UFO at about 0040 BST on 8 June but could not capture any images before the object vanished over the Bristol Channel.
South Wales Police said the helicopter did not give chase and described the crew as very experienced. The sighting has been reported for investigation.