Almost 30 privacy activists and human rights groups sent a letter to Congress this week urging House members not to fund “various invasive surveillance technologies” at the U.S.-Mexico border, citing privacy and civil liberty concerns.

The letter decries the House Democratic Conferees Proposal for Smart, Effective Border Security, which suggests using surveillance cameras at the border to improve security and facilitate safe border crossing.

Not only do surveillance cameras intrude on the civil liberties of Americans crossing the border, the activists argue, but it would also violate the rights of Americans living near the border.

“The proposal calls for ‘an expansion of CBP’s air and marine operations along the border,'” the activists wrote in the letter. “We are concerned this means an increase in the deployment of aircraft with wide-area surveillance capabilities. Such aircraft, including unmanned drones, often include the power to capture the faces and license plates of vast numbers of people who live and work near the border. The government may scrutinize this personal information with machine-learning techniques susceptible to the same biases and problems listed above. Vendors already are applying artificial intelligence software to images captured by mounted cameras. Given the Department of Homeland Security’s particular history of using drones wastefully and irresponsibly, we do not believe there should be an expansion in their use.”

The activists oppose using license plate readers and biometric screening which, the argue, could violate Americans’ Fourth and Fifth Amendment rights and track citizens’ locations, and object to  “risk-based targeting” efforts that use black-box algorithms, which could exacerbate racial profiling at the border.

Following up on the letter, privacy think tank Electronic Frontier Foundation (EFF) released a statement calling on American citizens to protest the Democrats’ “tech wall,” which could violate their privacy as well as foreigners’ basic human right to privacy.

According to an EFF blog post, there is potential for grave misuse of certain technologies at the border. To best protect citizens’ privacy, Democrats should not give the federal government more surveillance powers. (The EFF documents government surveillance in the U.S. on its website.)

“The federal government already conducts face surveillance of all travelers (U.S. citizens and foreign nationals alike) on certain international flights,” EFF legislative activist Hayley Tsukayama said. “Other threats include iris scans, voiceprints, or even collection of DNA information. Given the sensitivity of biometric information, EFF is concerned about the threat that any collected data will be stolen or misused, as well as the potential for such programs to expand far beyond their original scope.”

Because President Donald Trump’s physical wall proposal would involve seizing private property from citizens along the border, it could be argued that his proposal is a threat to property rights, but the EFF argues a “tech wall” would be worse for American citizens and a pivotal infraction of constitutional rights.

“The proposal to build a physical barrier at the border has been roundly criticized. We should not deploy a variety of invasive technologies that violate everyone’s civil rights in its place,” Tsukayama said.

Follow Kate on Twitter