High-definition video shows a mysterious cube-shaped UFO appearing to hover over a major city.

A commercial jet is seen flying close by the silvery craft, which was reportedly filmed near an airport on Monday.

Lorna Mosquera posted footage on YouTube he said was filmed on 4K mode on his iPhone 13 Pro in Medellin, Colombia.

It shows the view from his apartment balcony, looking over other tower blocks and mountains in the distance.

A dark object can be seen a few thousand feet up, and he zooms in to show a closer view of what appears to be a metallic cube or diamond.

"Guys, what the hell is that?" he is heard asking on the clip.

To read more and view the video, click here.