Special Counsel Robert Mueller likely will not testify before Congress until after the Memorial Day recess, postponing his appearance until some time in June, according to House Democrats and a spokesperson for Mueller.

Judiciary Chairman Jerry Nadler, D-N.Y., had set a deadline of May 23 for Mueller to publicly testify after the April release of a redacted version of the special counsel’s 448-page report was released to Congress.

But the proposed schedule became increasingly uncertain as a broader dispute developed between House Democrats and Attorney General William Barr over access to underlying documents and testimony associated with the special counsel’s investigation into whether Russian operatives colluded with the Trump campaign to influence the outcome of the 2016 presidential campaign.

Nadler’s committee voted last month to hold Barr in contempt of Congress for refusing to release the full report.

What is known about the special counsel’s report, even from the redacted version, is Mueller found no criminal conspiracy of any kind, but questions remain regarding possible obstruction of justice.

Barr told the Wall Street Journal late last week that it was up to Mueller to decide whether to testify and that Barr was placing no constraints on the special counsel.

At this point, Democrats and Mueller have yet to reach agreement on a schedule for hearings before both the Judiciary and House Intelligence committees. A Mueller spokesman declined to comment Friday regarding the special counsel’s appearance at the Capitol. Mueller remains a government employee and still oversees a small staff as he closes down his office.

However, sources say, hearings could be convened before the recess if Mueller decided to make an appearance this week.

The hearings, when and if they occur, are likely to cover a wide range of topics, from the lack of evidence of collusion, and the special counsel’s decision not to charge the president with obstruction of justice. Republicans see the hearings as an opportunity to vet the possibility the investigation was politically motivated and potentially instigated by FBI agents who shared anti-Trump text messages. Democrats also want to know more about why Mueller criticized Barr in a letter after the release of the redacted report, in which he argued Barr failed to “fully capture the context, nature and substance” of the Russia probe.

Meanwhile, President Trump tweeted earlier this month that Mueller should not testify and he has threatened to invoke executive privilege to prevent the release of a full version of the report.