(Bloomberg) -- Salesforce.com Inc. Chief Executive Officer Marc Benioff rejected calls from employees to reconsider business ties with U.S. Customs and Border Protection over the separation of immigrant families, saying the company’s software isn’t involved in the agency’s policy at the U.S.-Mexico border.

“I’m opposed to separating children from their families at the border. It is immoral,” Benioff wrote Wednesday in a memo to Salesforce employees obtained by Bloomberg News. “I have personally financially supported legal groups helping families at the border. I also wrote to the White House to encourage them to end this horrible situation.”

More than 650 Salesforce employees signed a letter to Benioff that called CBP’s actions “inhumane” and asked the San Francisco-based company to reconsider its contract providing tools to help with recruiting and communications. Some workers spoke Monday to Tony Prophet, the chief equality officer, about the letter, Bloomberg News reported. The staff’s effort is part of a growing wave of employee activism within the tech industry, as workers question how their products are used by U.S. law enforcement and the military.

Salesforce, which added the border agency as a customer in March, pledged $1 million to help families affected by the Trump administration policy. A federal judge Tuesday ordered the U.S. to reunite immigrant children who were separated from their families at border crossings.

Benioff -- known for his prolific use of social media and his progressive political views -- was slow to respond to the letter, which began circulating within Salesforce last week. He has been on vacation since June 18, he wrote in the memo, and won’t return to the office until July 15. In the meantime, Chief Operating Officer Keith Block said on Twitter that Salesforce’s philanthropic arm will match employee donations on the issue.

Benioff, in his memo, said he “heard” the concerns “and I’m very proud of all our employees for organizing actions supportive of families at the border.”

To contact the reporters on this story: Nico Grant in San Francisco at ngrant20@bloomberg.net;Mark Bergen in San Francisco at mbergen10@bloomberg.net

To contact the editors responsible for this story: Jillian Ward at jward56@bloomberg.net, Andrew Pollack, Alistair Barr

©2018 Bloomberg L.P.