Jacob Hamilton/Ann Arbor News via AP Former Secretary of State Hillary Clinton will no longer be participating in the Fortune Most Powerful Women Summit next week.

Hillary Clinton will no longer be speaking at the Fortune Most Powerful Women Summit next week amid controversy that the event will feature Kirstjen Nielsen, President Donald Trump’s former homeland security secretary who oversaw the migrant family separation policy.

The news was first reported by Slate on Friday and confirmed by HuffPost. Clinton spokesman Nick Merrill cited a scheduling conflict.

But a source familiar with the decision told HuffPost that Nielsen’s inclusion was the reason the former secretary of state and 2016 presidential candidate withdrew. Fortune did not immediately return a request for comment.

Nielsen resigned from the Trump administration in April. As secretary of the Department of Homeland Security, she executed and defended his policy of separating and detaining thousands of migrant families crossing into the United States.

The Fortune Most Powerful Women Summit is a gathering of prominent women across industries, set to take place next week in Washington, D.C.

Nielsen was originally part of a panel called “Conversation,” which would focus on the more controversial parts of her legacy at DHS but also “supply chain risk management.”

That discussion was later changed to “The Hard Questions.” Fortune spokeswoman Alison Klooster explained that it was because one of the other panelists dropped out, so they had to change the format. She said the event will be a “no-holds-barred interview” with “tough questions” both from a journalist moderator and the audience.

On Friday, filmmaker, activist and author dream hampton also withdrew from the event because of Nielsen’s participation.

“Fortune should not be giving Kirstjen Nielsen a platform to rehabilitate her image,” hampton said. “I’ve worked all my life to tell the stories of women, girls and families. Sharing a stage with Nielsen, who separated immigrant families and put babies in cages, would have put a stamp of approval on her immoral and reprehensible actions and help legitimize the terror that Trump is inflicting on immigrants and communities of color.”

She also said she was encouraging other speakers to pull out as well, unless Fortune rescinded its invitation to Nielsen.

Activist groups including Credo Action, Define American and Bend the Arc have been pressuring Fortune to remove Nielsen.

“As a mother, I am stunned and saddened that Fortune 500 invited former DHS Secretary Kirstjen Nielsen to speak at its Most Powerful Women Summit next week,” said Khadija Gurnah, the organizing director of Define American. “Nielsen was the architect of the failed response to Katrina and somehow still got a big role in the Trump administration. Her policy of separating families at our southern border is barbaric. The utter lack of accountability in giving such a repellant character such a high-profile platform to speak hurts America and is awful for children at the border.”

Activists have also been following Nielsen since she resigned from the Trump administration in April, trying to ensure that her actions as homeland security secretary aren’t forgotten.

Nielsen pulled out of the Atlantic Festival in September after controversy and objections. In 2018, Credo held a protest outside her house, playing audio of detained migrant children crying.