Hours before former Trump campaign manager Corey Lewandowski was set to attend a rally with President Trump in New Hampshire, where he is seriously considering a Senate bid, the House Judiciary Committee announced it had issued a subpoena for his testimony.

House Judiciary Committee Chairman Jerry Nadler announced his committee is demanding that Lewandowski and Rick Dearborn, former deputy White House chief of staff, testify before the committee on Sept. 17. Democrats on the House Judiciary Committee claim Lewandowski and Dearborn played a role in the president obstructing former special counsel Robert Mueller's investigation.

"It is clear that any other American would have been prosecuted based on the evidence Special Counsel Mueller uncovered in his report. Corey Lewandowski and Rick Dearborn were prominently featured in the Special Counsel's description of President Trump's efforts to obstruct justice by directing then-White House Counsel Don McGahn to fire the Special Counsel, and then by ordering him to lie about it," Nadler said in a statement.

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Nadler pointed out that Mueller's report says Mr. Trump asked Lewandowski to direct former Attorney General Jeff Sessions to limit the Mueller investigation, and Mueller's report says Lewandowski asked Dearborn to deliver the message, which was ultimately never carried out.

The subpoena comes as Mr. Trump has all but endorsed Lewandowski for Senate in New Hampshire, before Lewandowski has announced whether he'll run. Mr. Trump offered glowing words for Lewandowski in a radio interview that aired Thursday.

"I will say this, if he ran he would be a great senator. If he ran and won he'd be a great senator. He would be great for New Hampshire, he'd be great for the country," Mr. Trump said. "He has got a tremendous drive and that drive would be put to the people of New Hampshire's benefit and the country's benefit."

Lewandowski was expected to be aboard Air Force One en route to the Granite State Thursday to discuss a possible Senate.

Rebecca Kaplan contributed to this report