Photos of an "early prototype" Google smartwatch made by Motorola reportedly leaked online Tuesday.

Called Google Watch and codenamed "Gem," the watch fell under the Nexus category of devices, according to Android Police, citing an anonymous source.

The grainy photos show a square display with a capacitive back button and two rocker buttons. In one image, the display features a settings menu.

It's not clear when the photos were taken, although Android Police reported the smartwatch was "believed to exist in 2013." Google sold Motorola to Lenovo earlier this year for $2.9 billion.

Earlier on Tuesday, Motorola confirmed via Twitter that it was working on a watch that will be available later this year, though it isn't clear whether the two products are related.

Rick - We are working on a watch that will be available this year. We aim to address consumer issues like style & battery life #MotoMWC

— Motorola Mobility (@Motorola) February 25, 2014

This is not the first time rumors of a Google smartwatch have surfaced. One was reportedly close to completion last October, just one month after Google acquired Android watchmaker Wimm.

Google did not immediately respond to a request for comment.

Have something to add to this story? Share it in the comments.