The Trump administration is trying very hard to convince the American people that it’s Congress, not the White House, that’s responsible for its “zero tolerance” immigration policy — the one that has left thousands of children separated from their parents at the border.

On Monday, Department of Homeland Security Secretary Kirstjen Nielsen was dispatched to the White House briefing room to face reporters’ questions about the administration’s decision to prosecute everyone who crosses into the United States without authorization.

“Congress and the courts created this problem, and Congress alone can fix it,” Nielsen told reporters in a press conference assembled just minutes after ProPublica released audio of detained children crying for their parents. “Until then, we will enforce every law we have on the books to defend the sovereignty and security of the United States.”

Attorney General Jeff Sessions kicked off the administration’s “zero tolerance policy” in May, which mandates that all migrants crossing the border illegally be prosecuted. Since migrants facing criminal prosecutions are held in federal jail, which cannot house minors, they are separated from any children who came with them.

Under past administrations, undocumented migrants typically underwent civil deportation procedures and often allowed to remain with their children, either through being released or held in family detention centers.

Some saw the policy, and the public outcry it generated, as an attempt to get Congress to act. “The children are not being used as a pawn,” Nielsen stressed. “We are trying to protect the children, which is why I’m asking Congress to act.”

But when a reporter asked why President Donald Trump doesn’t just reverse the policy, since his own administration implemented it, Nielsen all but confirmed that the president won’t stop separating families until he gets what he wants.

“I think what the president is trying to do is find a long-term fix,” she said. Over the past two days, Trump has repeatedly tweeted about “Border Security & Safety,” falsely blaming Democrats for splitting up migrant families.

Nielsen also snapped back at reports that immigration officials are stopping migrants from legally crossing the border and seeking asylum. Border officials aren’t turning people away, she said — they’re telling people to just come back later.

“If we do not have enough bed space, if we do not have enough medical personnel on staff, if we do not have enough caretakers on staff, then we will tell people that come to the border they need to come back,” Nielsen told reporters.

People have reportedly been forced to wait for days, in temperatures that top 100 degrees, before they were allowed to actually cross over the border.

Another journalist asked Nielsen whether the family separations are intended to send a message to potential migrants, to deter them from crossing the border at all. She replied, “I find that offensive. No. Because why would I ever create a policy that purposely does that?”

Both Sessions and White House chief of staff John Kelly, who previously served as the Department of Homeland secretary and as Nielsen’s boss, have suggested that the administration separate migrant families in order to deter them from coming to the United States at all.

“In order to deter more movement along this terribly dangerous network, I am considering exactly that,” Kelly told CNN’s Wolf Blitzer last March. “They will be well cared for as we deal with their parents.”

“If you smuggle an illegal alien across the border, then we’ll prosecute you for smuggling,” Sessions said in May. “If you’re smuggling a child, then we’re going to prosecute you. And that child will be separated from you, probably, as required by law. If you don’t want your child to be separated, then don’t bring ‘em across the border illegally. It’s not our fault if somebody does that.”