James McHenry, acting director of the Justice Department's Executive Office for Immigration Review, said the Trump administration would have to double the number of immigration judges to make a dent in the record-high number of pending cases.

"We've run several estimations and we've asked for additional judges," he told the House Judiciary subcommittee on immigration and border security Wednesday. "I think up to a total of 700 is where it starts to turn around."

Currently, EOIR employs 336 immigration judges nationwide and is allowed up to 384 judges.

"The next budget request brings it up to 449. The president has outlined a policy that would add 370, that gets to approximately 700," McHenry said.

The number of immigration cases on the docket is at an all-time high, according to McHenry. The 640,000 cases is nearly triple the number of cases the courts had in fiscal year 2009 and double that of fiscal year 2012.

Sixty-one judges have been hired since Jan. 1 and the hiring pace is expected to improve in the coming fiscal year.

"Hiring is a top priority for the agency, and the president’s immigration principles and policies call for continued effort[s] to hire up to an additional 370 immigration judges," McHenry added in a written statement. "The size and trajectory of the pending caseload will not reverse overnight, and the situation may continue to worsen in the short run before it gets better."

Rep. Steve King, R-Iowa, followed up with a question about the number of judges necessary to maintain levels once they come under control. McHenry said his office had not calculated those figures.