ORLANDO, Fla. -- Citing privacy concerns, the ACLU of Florida sent a letter to the Orlando City Council on Monday demanding that the city discontinue use of Amazon's facial recognition technology.

The Orlando Police Department was part of a pilot testing program for Amazon's Rekognition, which uses artificial intelligence to "identify the objects, people, text, scenes and activities, as well as detect any inappropriate content," according to the Amazon website. Rekognition also provides "highly accurate facial analysis and facial recognition."

The software can identify up to 100 people in an image by scanning faces and search against databases. The Orlando test uses existing cameras around the city.

The ACLU of Florida wants Orlando to cease deploying it to police and city agencies.

"Face surveillance systems like Rekognition present a grave threat to Orlando residents and visitors," the group's letter reads. It says Orlando could use Rekognition to track people without their knowledge or consent -- and alleges that Amazon has marketed it that way.

"The City Council has allowed the use of this technology by the Orlando Police Department without inviting public debate, obtaining local legislative authorization, or adopting rules to prevent harm to Orlando community members," Nancy Abudu, legal director of the ACLU of Florida, said in a news release. "...We demand the City of Orlando to uphold that standard and end the use of a tool that threatens public safety, and that will endanger the rights of communities of color, protesters, and immigrants."

Orlando Police said Monday that the city's test with the program ended last week. The ACLU says records indicate Orlando's test began in 2017.

"Staff continues to discuss and evaluate whether to recommend continuation of the pilot at a further date. At this time that process in still ongoing and the contract with Amazon remains expired," Orlando Police said in a statement.

"Partnering with innovative companies to test new technology -- while also ensuring we uphold privacy laws and in no way violate the rights of others -- is critical to us as we work to further keep our community safe," the statement said.

The ACLU has asked Amazon to stop marketing Rekognition to government agencies.

Last week, a coalition of groups sent a letter addressed to Orlando Police Chief John Mina, asking him to discontinue the pilot program.

The groups include the Arab American Community Center of Florida, the Florida Immigration Coalition, NeJame Law, the Orange County Classroom Teachers Association, the United Faculty of Florida at UCF and Mi Familia Vota.

"Communities that already feel under attack by government and law enforcement will be less likely to engage with the OPD, even when they are victims of crime," the letter read.

Last month, Mina held a news conference after privacy advocates expressed concern that the technology could be abused. He said several of his officers had volunteered to be a part of the test, which Mina said included three cameras in public places in the city as well as several other cameras at OPD headquarters in downtown Orlando.

Orlando International Airport last week announced it would become the first airport in the nation to implement facial recognition technology on international travelers.