Washington, April 21 (IANS): An "unexplained" object seen in an 1960 image taken by a NASA probe could be an alien spacecraft, claims a UFO enthusiast.

Scott C. Waring said the unexplained object in the image taken in 1960 by an unmanned NASA probe sent out during the Mercury project in the early days of the US's space exploration could be an alien spaceship.

Waring believes alien observers have been keeping an eye on mankind's missions into space from the beginning, media reports said.

He saw the anomaly on the picture captured by space capsule Mercury-Redstone 1A on December 19, 1960.

"I found a disk in some photos of the Mercury mission. The mission took place in December of 1960, and why wouldn't aliens be interested in watching a historical moment in human history?" Waring wrote on his blog, which charts evidence of UFOs and alien life.

"Especially since the capsule was unmanned, there were no worries that they would be seen. It's actually the earth in the background and the UFO is in space observing the Mercury capsule," he said.

"The disk is hard to make out in the first photo, but three photos later it's easy to see. It looks like a classic disk with a wedge cut out of it," he added.

Project Mercury was the first US mission. There were also six manned space flights, including a February 1962 mission when John Glenn became the first American to orbit the Earth.