Nine US privacy groups have dropped out of talks on voluntary standards for facial recognition technology, after failing to agree on a code on how it could be deployed.

The walkout, announced Tuesday, deals a setback to US government-sponsored discussions aimed at reaching a compromise with consumer advocates and companies using facial recognition for electronic commerce, law enforcement, security or other purposes.

"We believe that people have a fundamental right to privacy. People have the right to control who gets their sensitive information, and how that information is shared," said a letter from the nine organizations including the American Civil Liberties Union, the Center for Democracy & Technology and the Electronic Frontier Foundation.

"And there is no question that biometric information is extremely sensitive. You can change your password and your credit card number; you cannot change your fingerprints or the precise dimensions of your face. Through facial recognition, these immutable, physical facts can be used to identify you, remotely and in secret, without any recourse."

Other participants dropping out were from the Center for Digital Democracy, Consumer Action, Consumer Federation of America, Consumer Watchdog, Common Sense Media and the Center on Privacy & Technology at Georgetown University.

- Pushing for 'opt-in' -

The move comes amid growing concerns on facial recognition technology, which analyzes facial features and can be used to find criminal suspects as well as for marketing purposes.

EFF has expressed concerns over an FBI database with some 14 million face images and efforts by law enforcement to use "tagged" photos on social networks such as Facebook.

"We, along with the other privacy groups, advocated for an opt-in regime so that people can choose whether they participate in a face recognition database," EFF's Jennifer Lynch said in a blog post.

"After 16 months of active engagement in the process, we decided this week it was no longer an effective use of our resources to continue in a process where companies wouldn't even agree to the most modest measures to protect privacy."

The letter from the nine groups said that "at a base minimum, people should be able to walk down a public street without fear that companies they've never heard of are tracking their every movement... Unfortunately, we have been unable to obtain agreement even with that basic, specific premise."

The US government's National Telecommunications Information Administration said in a statement it was "disappointed that some stakeholders have chosen to stop participating in our multi-stakeholder engagement process" but that the talks would go on.

"A substantial number of stakeholders want to continue the process and are establishing a working group that will tackle some of the thorniest privacy topics concerning facial recognition technology," the statement said.

The talks have included several technology industry groups and companies, and groups representing the retail and electronic commerce industries.

- Meaningful control -

NetChoice, an e-commerce trade association, said it hopes the privacy groups will return but that their absence "won't stop us from trying to create a workable code of conduct for facial recognition privacy."

"We all want the same outcome -- to help users be comfortable using online services with confidence that their privacy will be protected," the group said in a statement.

"We think we can reach consensus on transparency, notice, data security, and giving users meaningful control over the sharing of their facial recognition information with anyone who otherwise would not have access."