Robert Mueller may be one step closer to being questioned in public on Capitol Hill, with a representative of the special counsel saying he has agreed to testify before Congress, according to a Democratic congressman on Sunday.

The Rhode Island congressional representative David Cicilline said a “tentative date has been set of May 15” for Mueller to testify, he told host Chris Wallace on Fox News Sunday.

“We hope that the special counsel will appear,” he said at first.

Pressed on whether Mueller had actually agreed to testify, he added that “a representative for the special counsel has”.

Cicilline couched his remarks by saying that “obviously”, Congress would not know definitely that Mueller is testifying on this date until the day comes.

He appeared to wobble on his declaration a little later, tweeting: “Just to clarify: we are aiming to bring Mueller in on the 15th, but nothing has been agreed to yet. That’s the date the Committee has proposed, and we hope the Special Counsel will agree to it. Sorry for the confusion.”

On Sunday afternoon, the president said on Twitter that “Bob Mueller should not testify”.

Trump posted, in part, in two back-to-back tweets: “Why would the Democrats in Congress now need Robert Mueller to testify? Are they looking for a redo because they hated seeing the strong NO COLLUSION conclusion?”

....to testify. Are they looking for a redo because they hated seeing the strong NO COLLUSION conclusion? There was no crime, except on the other side (incredibly not covered in the Report), and NO OBSTRUCTION. Bob Mueller should not testify. No redos for the Dems! — Donald J. Trump (@realDonaldTrump) May 5, 2019

Mueller’s report last month had found a lot of evidence of interactions between the Trump campaign and Russia during the 2016 election, but did not conclude that any of it amounted to criminal conspiracy. Mueller also found multiple instances where Trump tampered with the investigation and would have obstructed further if he had had his way and not been protected by those around him.

The special counsel ultimately did not rule on whether the crime of obstruction had been committed by Trump, leaving that decision for others, while saying he could not exonerate the president. His redacted report also left questions unanswered.

The attorney general, William Barr, and departing deputy attorney general, Rod Rosenstein, decided there had been no criminal obstruction, while Democrats in Congress are insisting on more information and investigation before they decide on further action.

Cicilline’s statements about Mueller’s possible testimony come amid heightened tensions between Congress and the Department of Justice, especially its head, Barr, over the report resulting from an almost two-year investigation into allegations of collusion between the Trump 2016 campaign and Russia, and obstruction of justice.

Barr has been widely criticized for presenting an overly rosy view of Trump in his four-page summary of Mueller’s report last month. Several Democrats, especially the House speaker, Nancy Pelosi, and several 2020 presidential candidates, led by Elizabeth Warren, have called for his resignation.

Pelosi also accused Barr of lying to Congress about statements he made regarding criticism of his handling of the report by Mueller, with the senior Democrat declaring last week: “That’s a crime.”

Barr has been accused of casting the 448-page report to make it seem as if Mueller definitively determined that there was no cooperation or collusion between the president, his campaign and the Russian government.

The Mueller report, however, contains numerous details about ties between Trump associates and the Russian government, and at least 11 attempts by Trump to block Mueller’s investigation.

Barr’s appearance before the Senate judiciary committee on Wednesday was characterized by seeming defensiveness, after it was revealed that Mueller had privately criticized his initial public summary of the report.

During Barr’s testimony, he called Mueller’s letter “a bit snitty”, and intimated that it might have been penned by one of the special counsel’s staff.

Barr was a no-show at a congressional oversight hearing on Thursday due to a dispute over questioning protocol. Barr reportedly took issue with both parties’ plans to have their counsels question him, not just the members of Congress themselves.

The House judiciary committee chairman, Jerry Nadler, a Democrat of New York, has given Barr a Monday deadline of 9am ET to turn over additional portions of the report and the evidence behind it.

Cicilline told Wallace that if Barr does not comply, Nadler appears poised to push forward with contempt proceedings.

“There has not been compliance yet,” Cicilline said of Barr turning over these documents. “I think if the attorney general does not, the chairman will ask the committee to move forward with a contempt citation.”

“I hope the attorney general will comply,” Cicilline said, later adding, “If Mr Barr agrees to turn over what we’re requested in a reasonable way, nobody on the committee is interested in moving forward with contempt.”

A request for comment from the DoJ did not bring an immediate response.