A Google spokesperson declined Tuesday to comment on the matter on which the company had earlier tweeted: "We think you'll find Uber and Lyft work quite well. We use them all the time."

Also a ride-share company, Lyft is Uber's direct competitor. It was Google's response to the announcement of Uber's partnership with Carnegie Mellon University for research and development work in mapping and autonomy technology, two areas in which Google has made significant progress.

The company that puts riders in touch with private car owners in cities worldwide announced the creation of the Uber Advanced Technologies Center in Pittsburgh on its blog.

Google has invested hundreds of millions of dollars in Uber through its venture capital arm and its chief legal officer, David Drummond, is on the Uber board of directors.

According to media reports, Google too is planning to launch its own ride-hailing service in conjunction with its driver-less car project.

An anonymous source quoted by The Wall Street Journal said that reports that Google was developing an app to rival Uber had been blown out of proportion.

The source said that a Google engineer had been testing an internal app that helps Google employees carpool to work and denied that the app was associated with the company's driver-less cars programme.