The Federal Bureau of Investigation (FBI) announced on Monday the completion of its new facial recognition system, making operational a program that civil rights groups have warned risks turning millions of citizens with no criminal record into suspects.

Next Generation Identification (NGI), as the technology is known, was developed to expand the bureau’s biometric identification capabilities. Now, the NGI system will include automated fingerprint search capabilities, mobile fingerprint identification and electronic image storage, a press release by the FBI’s Criminal Justice Information Services Division said.

Whistleblower Edward Snowden revealed in June that the National Security Agency (NSA) pulls in millions of images to aid its own facial recognition program.

The FBI's facial recognition service “will provide the nation’s law enforcement community with an investigative tool that provides an image-searching capability of photographs associated with criminal identities,” the FBI release said.

But civil liberties watchdog Electronic Frontier Foundation (EFF) said the system poses a threat to the privacy of all Americans, including those with no criminal history.

EFF filed a Freedom of Information Act lawsuit for information on NGI in April. FBI documents they obtained showed that the facial recognition component of the system could include as many as 52 million digital images of faces by 2015, the group said.

Up to 4.3 million pictures taken for non-criminal purposes will also be added to the database, documents obtained by EFF showed. Mug shots will be combined with non-criminal facial images taken from employment records and background check databases, technology news website The Verge reported on Monday.

That means someone with no criminal history could be implicated as a suspect in a crime if an image of his or her face happens to be in the database, EFF warned.

Compounding that risk is the apparent ineffectiveness of the system, with some in the industry saying the image matching system has a low rate of success, according to the Verge report.

The FBI, for its part, has said the system is not designed to give accurate identification. Instead, it is meant to provide a list of candidates — saying that if the true candidate exists in the system, it will appear in the top 50 candidates returned by the system 85 percent of the time, according to documents obtained by the EFF.

“This means that many people will be presented as suspects for crimes they didn’t commit,” EFF said.

Al Jazeera's request for comment from the FBI was not answered at the time of publication.

Rights groups have also raised concerns over who has access to the images, something to which the FBI release referred only vaguely.

“Law enforcement agencies, probation and parole officers, and other criminal justice entities will also greatly improve their effectiveness by being advised of subsequent criminal activity of persons under investigation or supervision,” the release said. “The IPS [Interstate Photo System] facial recognition service will provide the nation’s law enforcement community with an investigative tool that provides an image-searching capability of photographs associated with criminal identities.”

According to EFF, “the FBI and Congress have thus far failed to enact meaningful restrictions on what types of data can be submitted to the system, who can access the data, and how the data can be used.”

The FBI said in the documents it will not allow non-criminal photos like images from social networking sites into the system, but there are no legal restrictions to keep that from occurring at some point, EFF said.