On Tuesday, a group of 90 advocacy groups penned a letter to Amazon, Google, and Microsoft, requesting that the companies pledge not to sell facial recognition technology to the government.

The American Civil Liberties Union (ACLU), the Refugee and Immigrant Center for Education and Legal Services (RAICES), and the Electronic Frontier Foundation (EFF) were among the groups that pressed these companies. The letter marks mounting pressure on some of Silicon Valley’s most influential companies and their ramping efforts to build facial recognition systems.

“History has clearly taught us that the government will exploit technologies.”

“We are at a crossroads with face surveillance, and the choices made by these companies now will determine whether the next generation will have to fear being tracked by the government for attending a protest, going to their place of worship, or simply living their lives,” Nicole Ozer, technology and civil liberties director for the ACLU of California, said.

Recently, Google and Microsoft have acknowledged the risks involving facial recognition services and their potential for misuse and surveillance by bad actors. In December, specifically, Google announced that it would not sell its technology until these loopholes for abuse were closed. Microsoft president Brad Smith proposed several safeguards for the technology that Congress could put into law in order to stifle misuse, including reducing bias and requiring court orders for individual tracking. Still, these groups are seeking stronger pledges from both companies.

Amazon has been particularly aggressive in marketing facial recognition as part of its cloud platform. Last week, NextGov reported that the FBI was piloting Amazon’s facial recognition tech, Rekognition. Amazon’s CEO Jeff Bezos has made public remarks acknowledging the technology’s loopholes for abuse, but he has continued to pursue partnerships with the federal government. In October, Bezos said that Amazon would continue to seek a $10 billion deal with the Pentagon in which it would provide cloud services for the agency, despite backlash from employees. Google dropped out of the bidding for the deal, which has yet to be finalized.

Google, Amazon, and Microsoft did not immediately respond to requests for comment.

“Companies can’t continue to pretend that the ‘break then fix’ approach works,” Ozer said. “History has clearly taught us that the government will exploit technologies like face surveillance to target communities of color, religious minorities, and immigrants.”