Treasury Secretary Steve Mnuchin told Fox Business on Thursday he's comfortable with a three-month deal to increase the debt ceiling. 

President Donald Trump on Wednesday split with congressional GOP leaders to support a Democratic approach on Hurricane Harvey relief coupled with a three-month extension on federal borrowing authority and government funding. 

Senate Majority Leader Mitch McConnell later said he would support the package. 

Just hours before the president's White House meeting with leaders from both parties, House Speaker Paul Ryan called a three-month debt limit increase proposed by Democrats "ridiculous" and "unworkable."  A short-term extension would disadvantage Republicans in future fiscal negotiations. 

"We're very happy we have a deal," Mnuchin told Fox. 

"The president's priority was to make sure we have the funding for Harvey and to make sure we raise the debt limit to pay for that," he added. " We've accomplished that." 

"Everybody in the room was very clear that we would never let the government default" on its debt, said Mnuchin. 

On tax reform, Mnuchin said it's "still very viable" this year. 

"The major blueprint has been outlined," he said. " The [congressional] committees will add to parts of this." 

Mnuchin also said Trump has not made any decisions on additional appointments to the Federal Reserve. 

As speculation swirled around the future of Fed Chair Janet Yellen, Vice Chair Stanley Fischer announced his resignation Wednesday, effective next month.  He cited personal reasons. 

Trump already has nominated Randal Quarles to one of the other Fed vacancies. 

Mnuchin will be speaking next week at CNBC's Delivering Alpha conference. 

CORRECTION: This story has been updated to correct the spelling of Treasury Secretary Steven Mnuchin's name.