Images of the rumoured Google X Phone appear to have leaked online, Digital Spy said.

A Motorola-branded device surfaced on the Twitter account of tech tipster @evleaks.

Rumours surrounding a Google-developed device have heated up over recent months, following the web giant's acquisition of Motorola in 2011.

IGN reports that a job vacancy related to the project appeared on Linkedin for a brief period before it was quickly removed in January, fueling initial speculation that the 'X Phone' could be coming soon.

Similar images were also leaked in March by Vietnamese website Tinhte.vn, but neither Google nor Motorola have even confirmed the existence of such a phone.

Google's I/O conference takes place in San Francisco on May 13, when the company could shed some light on the 'X phone'.