More than 100 Microsoft employees have protested against the company's work with US immigration, following a "zero tolerance" policy that resulted in children being separated from their parents.
The controversy surrounds a $19.4 million contract with US Immigration and Customs Enforcement (ICE) for the use of Microsoft's cloud computing software by the US border agency.
"We believe that Microsoft must take an ethical stand, and put children and families above profits," states the letter, which is addressed to company CEO Satya Nadella.
"Therefore, we ask that Microsoft cancel its contracts with US Immigration and Customs Enforcement (ICE) immediately, including contracts with clients who support ICE.
"We also call on Microsoft to draft, publicize and enforce a clear policy stating that neither Microsoft nor its contractors will work with clients who violate international human rights law."
Microsoft CEO Satya Nadella responded by sending an email to all Microsoft employees, in which he called the policy of separating families "abhorrent," especially considering that he was an immigrant.
"My story would not have been possible anywhere else," Mr Nadella said in the email, which he shared on LinkedIn.
"This new policy implemented on the border is simply cruel and abusive, and we are standing for change."
He went on to reiterate a blog posted by Microsoft president Brad Smith on Tuesday, 19 June, which denied Microsoft's involvement with the US government on any projects relating to splitting up families at the US-Mexico border.
Microsoft is the latest technology giant to come under scrutiny for its partnerships with government agencies, following Google's Project Maven and
"Microsoft is not working with [the US governemnt] on any projects related to separating children from their families at the border, and contrary to some speculation, we are not aware of Azure or Azure services being used for this purpose," a company statement read.
Google has Project Maven. Amazon has Rekognition. Microsoft has this ICE contract. Salesforce is modernizing CBP. Palantir is...Palantir. The entire tech industry is complicit, and fighting it requires us to organize throughout the industry, across roles, companies, and borders.— Tech Workers Coalition (@techworkersco) 19 June 2018
Other tech leaders to speak out against the ICE policy include Apple's Tim Cook, who called the immigration policy "heartbreaking", and Google's Sundar Pichai.
"The stories and images of families being separated at the border are gut-wrenching," Mr Pichai said on Twitter.
"Urging our government to work together to find a better, more humane way that is reflective of our values as a nation."