Washington (CNN) California Democratic Sen. Kamala Harris said she believes the standoff between the Trump administration and Congress could mean the US has reached a "constitutional crisis."

"I think it is fair to say that we are looking at a crisis, not only of confidence, but potentially a constitutional crisis," Harris said in an interview that aired Sunday on CNN's "State of the Union."

Harris' comments came after some Democrats in Congress invoked the term over refusals from the Trump administration to accept demands for testimony and documents, including the full version of special counsel Robert Mueller's report. The standoff reached a high point last Wednesday, when the House Judiciary Committee voted to hold Attorney General William Barr in contempt after President Donald Trump invoked executive privilege over the Mueller report.

The committee's chairman, New York Democratic Rep. Jerry Nadler, said on Wednesday that while the term "constitutional crisis" had been overused, it was an apt description for the ongoing impasse between the two branches of government.

"We are in one because the President is disobeying the law, is refusing all information to Congress," Nadler said.

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