Washington (CNN) Acting chief of staff Mick Mulvaney maintained Sunday that President Donald Trump will use his executive authority to get funding for a wall on the southern border if he doesn't get it through Congress.

Mulvaney, speaking on "Fox News Sunday" two days after Trump agreed to reopen the federal government despite not receiving any money for his wall, also suggested that Trump, for now, is sticking to his request for $5.7 billion.

"I think ultimately he'll be judged by what happens at the end of this process, not by what happened this week," Mulvaney said.

He said the $5.7 billion request is for the construction of a wall along 243 miles "where we need it the most and where we need it the quickest."

"This is not something where he's married to a number," Mulvaney argued, noting the request is based on what the experts say is needed. He repeatedly declined to answer a direct question about whether the President would take less than $5.7 billion.

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