As many as 500 Amazon employees have signed a letter to executives calling for Peter Thiel’s Palantir to be banned from Amazon Web Sevices for working with ICE.

Forbes reports that Amazon is facing pressure from employee to cut ties with Peter Thiel’s Palantir, a data mining firm that is employed by ICE in its efforts to carry out deportations. Amazon employees are now circulating a letter from June 2018 in which they called for executives to ban Palantir from Amazon Web Services; Palantir’s software utilizes Amazon’s cloud computing unit.

More than 500 Amazon employees have reportedly signed the letter which is addressed to Amazon CEO Jeff Bezos and AWS head Andy Jassy. Last year, only 450 employees had signed the initial letter. “Our demands have become even more urgent given recent news. The U.S. government has been responsible for detaining people, including young children, in concentration camps under horrific conditions,” the email reads.

Palantir, which was founded by venture capitalist and Trump supporter Peter Thiel, has come under scrutiny for some time as its software has been used by ICE agents to identify illegal immigrants, according to the Intercept“This is a horrifying violation of human rights—and it’s powered by AWS,” the email reads.

A group of protesters including pro-immigration groups such as Mijente and Jews for Racial and Economic Justice interrupted the keynote speech at Amazon’s annual AWS Summit recently, with more than 500 protesters outside the event.

In one video, a protester shouts: “You just heard the voices of and the tears of children being held in detention facilities. Cut your ties to ICE Vogel, and all you tech workers are being complicit.”

Lucas Nolan is a reporter for Breitbart News covering issues of free speech and online censorship. Follow him on Twitter @LucasNolan or email him at lnolan@breitbart.com