Steve Bannon, US President Trump’s former chief strategist, on Wednesday said that before Elon Musk pulls back from his work with the Department of Government Efficiency, he needs to make clear what fraud and waste in the federal government has been uncovered.

“We need to have a very specific accounting of what he found as far as fraud goes and waste, and I mean details,” said Bannon. “None of this makes sense.”

Bannon also said he wants a letter of certification showing that no one has taken any data from the Trump administration or government, to which Semafor’s editor-in-chief Ben Smith asked, “Sounds like you don’t trust [Musk] not to take data?”

“Trust, but verify,” Bannon responded.

While Bannon has supported DOGE’s efforts, he has called Musk “evil,” in an escalating clash with the tech billionaire. Bannon said Wednesday that DOGE was “a blunt force instrument” that was needed to gut government waste, but that the cuts made to the federal government so far are only “programmatic,” noting that DOGE hasn’t turned up much from the Pentagon.

The Pentagon and other facets of the federal government’s discretionary spending are where Bannon wants to see budget cuts to pay for tax cuts.

“Unless you do that, the math doesn’t work out,” Bannon said, noting that the US has added $1.3 trillion to the federal deficit so far this year. “The current system we have is not sustainable. It’s just not.”

Bannon, a vocal advocate of raising taxes on millionaires, also urged the Trump administration “to do what they’re talking about,” referring to recent reports that the president’s inner circle is considering this.