Treasury Secretary Steven Mnuchin called on Congress Monday to raise the federal debt ceiling without conditions, saying that delaying the vote would do harm in financial markets.

"Markets don't want us to wait. The sooner we do this the better," Mnuchin told a House appropriations committee.

He added that he is the spokesman for the Trump administration on matters pertaining to the debt ceiling. Office of Management and Budget Director Mick Mulvaney had said that he would advocate for attaching spending reforms to a debt ceiling vote.

Previously, Mnuchin had asked Congress to raise the debt ceiling before leaving for its August break.

On Monday, he said he was confident that the Treasury could continue to pay the nation's bills through early September but declined to give a more specific timeline.

The federal debt bumped up against the $20 trillion limit this spring, and since then Mnuchin has been shifting around federal accounts to make incoming payments.

The best outside estimate indicates that he will run out of options in October or November, at which point he will no longer be able to guarantee that the government will pay all its bills on time and in full.

Defaulting on the debt would cause significant market disruptions and ruin other countries' faith in the dollar, Mnuchin testified Monday.