The bill, titled the Secure Data Act, was originally introduced into Congress in 2014 by Democrat Zoe Lofgren of California, according to a report in Cyberscoop on Thursday US time.

Its provisions are stark: unless there is a mandate under the Communications Assistance for Law Enforcement Act, "no court may issue an order to compel a manufacturer, developer, or seller of covered products to design or alter the security functions in its product or service to allow the surveillance of any user of such product or service, or to allow the physical search of such product, by an agency".

The politicians' move comes in the wake of some in their ranks questioning recent claims by the FBI that it could not gain access to 7800 mobile devices last year.

Their doubts were expressed in a letter to FBI director Christopher Wray about the agency's actions in the 2016 stoush with Apple, over gaining access to an iPhone 5C belonging to a terrorist who had killed Americans in San Bernardino, California, in December 2015.

In a statement, Lofgren was quoted as saying: "It is troubling that law enforcement agencies appear to be more interested in compelling US companies to weaken their product security than using already available technological solutions to gain access to encrypted devices and services."

A co-sponsor of the bill, Republican Thomas Massie of Kentucky, said: "Backdoors in otherwise secure products make Americans’ data less safe, and they compromise the desirability of American goods overseas."

Cyberscoop said other sponsors of the bill were Ted Lieu of California and Jerrold Nadler of New York (both Democrats), and Matt Gaetz of Florida and Ted Poe of Texas (both Republicans).

Last week, a coalition of big technology firms, for a second time in recent months, called for strong encryption not to be tampered with, and criticised efforts by law enforcement agencies to create backdoors.

Their call came after former Microsoft employee Ray Ozzie added fuel to the fire over the encryption debate, claiming that he had found a way for governments to bypass encryption without having to resort to a backdoor.

But his claims were panned by cryptographers and researchers alike, with one, Matthew Green, a cryptographer and professor at Johns Hopkins University, pointing out that Ozzie's scheme was "effectively a key escrow system for encrypted phones".

The debate over encryption and the provision of backdoors for law enforcement to gain entry has also been going on in other countries, with Australian Home Affairs Minister Peter Dutton stating in a speech in February that companies that provide encryption for communications would be forced to devise a means of giving government agencies access to encrypted messages.

And last year, former British Home Secretary Amber Rudd went on the record saying that "real people" do not need end-to-end encryption.