The Trump administration wants federal spending on Hurricane Harvey relief efforts to be tied to raising the debt limit.

"Without raising the debt limit, I'm not comfortable that we will get the money that we need this month to Texas to rebuild," said Treasury Secretary Steven Mnuchin on Fox News Sunday. "That's our priority. We need to help the people in Texas, and we need to get that done."

Mnuchin said both he and President Trump support the plan. Should Congress approve an aid package but not raise the debt ceiling, Mnuchin said the Treasury won't be able to pay for the relief Texas needs.

That's because without an increase or suspension of the debt limit, the Treasury Department would lack legal authority to resume borrowing. Because the government spends more money than it takes in, it must borrow to make up the difference.

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The Trump administration on Friday asked Congress to approve a $7.85 billion package as part of an initial request for funds in response to Hurricane Harvey, which dumped 51 inches on rain on some parts of Texas and is expected to leave about 30,000 people in need of temporary shelter. Two estimates put total losses at as much as $75 billion.

A request for more money is expected later this month.

At the time, a senior administration official told CNN that the White House expected the disaster funding and the debt ceiling to be paired in the Senate.

If the debt ceiling isn't adjusted before October 3, it's not just the Harvey relief effort that could be at risk.

A recent analysis from the Bipartisan Policy Center estimates the federal government could struggle to pay nearly 25% of the country's bills for that month if the current limit stays in place.

Related: Businesses donate over $157 million to Harvey relief efforts

Republican leaders have promised that the debt ceiling will be raised in time. But there's not yet an indication that lawmakers have come to a consensus on how to get it done.

Trump has been vocal on the issue, and he's suggested tying the debt ceiling issue to other measures in the past.

About two weeks ago, Trump chided Senate leader Mitch McConnell and House speaker Paul Ryan for not linking it to a veterans' health care reform bill.

"I requested that Mitch M. & Paul R tie the Debt Ceiling legislation into the popular V.A. bill (which just passed) for easy approval. They didn't do it so now we have a big deal with Dems holding them up (as usual) on Debt Ceiling approval. Could have been so easy-now a mess!" Trump wrote on Twitter.

On Sunday, Mnuchin again called for lawmakers to "put politics aside" and get it done.

--CNN's Kevin Bohn, Jeremy Diamond, Joe Johns, Deirdre Walsh and Kevin Liptak and CNNMoney's Jeanne Sahadi contributed to this report.