Two images from the official Nasa website show a UFO moving across Nasa's Curiosity rover as it conducts its survey of the Mars surface.
The disc-shaped UFO in the black and white images was spotted by UFO Sightings Daily's Scott C Waring, who posted the pictures on his blog. The tiny UFO is in the top-left corner of one of the images, and top-centre in another.
"Look at this awesome discovery in not one but two Nasa photos (Sol 369 and Sol 370). Both of which show the same UFO in different positions. These are typical alien flying saucers or discs that have been seen for many decades around the world", Waring, a UFO enthusiast wrote on his blog.
"These photos are directly from Nasa archives and have not been tampered with in any way...except possibly the NASA airbrush room at the Johnston Space Center," he added.
According to Nasa's Jet Propulsion Centre, a federally funded research and development wing, the images sent by the Mars rover earlier this month were taken by Rear Hazard Avoidance Cameras (Rear Hazcams). The images were posted under the Raw Images gallery in the website.
"Curiosity sends back raw images for current and prior Sols based on commands sent by the mission team. The rover uses orbiters to relay back a lot of its data, and maximises each opportunity when they pass by overhead", the website says.
In May this year, the internet was buzzing with another image from Nasa that captured a UFO hovering above the Earth's surface.
In the image, a disc-shaped object could be seen emitting strange rainbow-like colourful lights.
"Look carefully at the Nasa photo above and not only will you notice a UFO in it but if your computer screen brightness is higher, you will also notice that there is a glowing aura around the UFO," Waring wrote on his blog at the time.