US Attorney General William Barr has refused to testify to the Democratic-led House Judiciary Committee on his handling of the Russia inquiry.
Barr had previously objected to a plan for lawyers to ask questions at Thursday’s hearing, the BBC reported.
Committee chairman Jerrold Nadler accused the White House of a “complete stonewalling of Congress”.
The standoff raises the prospect that Barr, America’s top legal official, could be held in contempt of Congress.
On Wednesday, Barr was grilled by a Senate panel about his decision to clear President Donald Trump of obstruction of justice.
The defence of his actions before the Republican-led Senate Justice Committee came after Special Counsel Robert Mueller — who led the investigative hunt for links between the 2016 Trump campaign and Russia — expressed frustration over the report summary.
Mueller is expected to testify to Congress later this month.
A Department of Justice statement said Nadler had placed conditions on the House Judiciary Committee hearing that were “unprecedented and unnecessary”.
The department said that the planned move to have attorneys question Barr was unnecessary because most of the committee members were themselves lawyers.
However, Nadler told reporters he believed that Barr was afraid to testify on Thursday given “how dishonest he has been”.
“We plan on subpoenaing him if he decides not to show up. He can run but he can’t hide,” he said.
“I hope and expect that the attorney general will think overnight and will be there as well,” he added.
He testified for the first time on Wednesday since the release of Mueller’s 448-page report.
The special counsel did not establish any collusion between the Kremlin and the Trump campaign.
However, the report did not exonerate the president of obstruction of justice. It concluded the Republican president had repeatedly intervened with an inquiry that he feared would doom his presidency.
Barr, who was appointed by Trump, told the Senate Judiciary Committee he was “frankly surprised” Mueller did not reach a conclusion on whether the president had tried to obstruct justice.
The attorney general added that he was “absolutely” confident in his own judgment that Trump did not unlawfully attempt to impede the investigation.
“I think that if he felt that he shouldn’t go down the path of making a traditional prosecutorial decision, then he shouldn’t have investigated,” he said.
Barr’s testimony came after a letter he had received from Mueller was made public.
In the document, the special counsel stated that Barr’s summary “did not fully capture the context, nature and substance” of his report’s findings, and caused “public confusion about critical aspects of the results of our investigation”.