Bus commuters across the cities in the U.S. beware. Transit companies are increasingly investing in security systems that can actually record your conversations.

Well, if you happen to brush the news aside as you may have become accustomed to the surveillance cameras found inside the public transits, the new addition does indeed seem to infringe on privacy.

It appears that the transit authorities are quietly engaging in the microphone-enabled surveillance that provides them with ability to record and store private conversations, Wired has reported.

Funded by the Department of Homeland Security in some instances, there is widespread installation of microphones that employ cables or WiFi to match audio conversation with camera images to produce synchronous recording, the Daily has stated.

Apparently, the publication is in possession of copies of the contracts, procurement requests and other documents that appear to point to installation of such systems.

The news has raised serious concerns about security as the IP audio-video systems can be accessed remotely via a built-in web server, and can be employed with GPS data to track the movement of buses and passengers throughout the city.

In San Francisco, for instance, transit officials appear to have approved a $5.9 million contract for installation of new audio-enabled surveillance system on 357 buses and trolley cars over four years, with an option for 613 more vehicles. The contract, signed in July, specifies modern buses and historic trolley cars, according to the Daily.

Apparently, four and six camera/ microphone combinations are installed in each bus, giving transit authorities the ability to closely monitor passengers seated virtually anywhere, The Verge has indicated.

Bus companies seem to claim that the advanced surveillance systems offer the users great level of security. But such a move has drawn resistance from civil liberty and privacy-minded groups, who insist that it is in violation of existing laws.

However, nothing seems to stop the officials who are currently employing the technology in seven cities in the country.