The Sprint logo hangs on the side of its Fifth Avenue store in New York City. Google on Tuesday announced an alliance with Sprint to add the Internet giant's online telephone capabilities to mobile phones serviced by the US telecom firm.

Google on Tuesday announced an alliance with Sprint to add the Internet giant's online telephone capabilities to mobile phones serviced by the US telecom firm.

Sprint customers will be able to have calls to their numbers simultaneously ring at multiple phones such as home or office lines or even be routed to computers through Google's free email software.

"This basically gives Sprint customers all the benefits of Voice without the need to change or port their number," Google software engineer Jacob Hesch said in a blog post.

Whether Sprint users stick with original numbers or switch to Google numbers, Voice will replace Sprint and transcribe spoken messages for delivery by email or text messages.

More information was available at google.com/voice/sprint.

Google on Tuesday also announced an Android-powered handset tailored for Sprint's latest generation, high-speed 4G data network.

The Google-Sprint alliance came as US anti-trust authorities scrutinized plans by AT&T to acquire T-Mobile USA in a deal valued at $39 billion.

The deal that would allow AT&T to leapfrog Verizon Wireless and become the biggest US wireless provider.