The FBI, which hopes to gain the same access to voice communications that it has gained with e-mail through use of its controversial Carnivore snooping technology, made the request in a 32-page document sent to telecom companies earlier this month, The Wall Street Journal reported Wednesday.
The FBI's request was in the works before the Sept. 11 terrorist attacks, according to the report, but those events have lent new credence to the issue. Expanded law enforcement capabilities have been a priority since the attacks, with the new Patriot Act giving law enforcement broad powers amid criticism from civil libertarians.
The request encompasses both land-based and wireless networks, potentially including companies such as Qwest Communications International and AT&T Wireless, for example.
The FBI is concerned about technological developments in networks and their ability to keep up with accompanying surveillance techniques, the report said.
In recent years, a new wave of communications based on "packet" technologies has changed the way telecom companies transmit phone calls, allowing a voice call to be broken down into numerous bits and reassembled at its destination. That makes surveillance and tapping of such transmissions more difficult.
The FBI's request was made under the 1994 Communications Assistance to Law Enforcement legislation, which requires phone companies to tweak their networks so authorities can conduct surveillance.