A US House panel voted unanimously Monday in favour of publicly releasing the Democratic rebuttal to President Donald Trump and fellow Republicans' claims that the FBI abused its powers while investigating his campaign.

"The vote was unanimous to release this," Adam Schiff, the top Democrat on the Republican-controlled House Intelligence Committee, told reporters.

The panel's action sets up a clash with Trump, who has five days to review the request to release the document.

Democrats had pushed to have it published after Republicans voted along party lines to declassify their own memo over objections by the FBI and Justice Department.

Trump had strongly backed the release of the Republican memo last week. Should Trump refuse to declassify the Democratic version, a standoff between the White House and Democrats could follow.

Republicans "found themselves in an insupportable position when they released a misleading memo and refused to release the Democratic response, so I think they were compelled to take the action they did today," Schiff said.

The panel voted last week to declassify a memo composed by Chairman Devin Nunes that claims Democrat-funded research prompted the Federal Bureau of Investigation to spy on a former Trump campaign aide.

Democrats feared Trump would use the memo as a pretext for firing senior officials and subvert the investigation, led by Special Counsel Robert Mueller, into Russia's meddling in the 2016 US election and possible coordination between Trump's camp and Moscow.

Schiff, concerned that the White House might "redact our memo for political purposes," said he has asked the FBI and Justice Department to review his document and report back on what redactions, if any, they would make to protect classified information.

Top Senate Democrat Chuck Schumer said that, as a matter of "full transparency," and given that Schiff's memo is based on the same underlying documents as the Republican's document, the president should be fully prepared to release it.

"If he refuses, the American people will be forced to wonder: what is the president trying to hide?" Schumer said.

Critics have warned that releasing evidence during a prominent investigation that could reach the highest level of government would set a dangerous precedent.

Meanwhile, Trump's lawyers have urged him to refuse to sit down with Special Counsel Robert Mueller as part of the probe into his campaign's ties with Russia, The New York Times reported Monday.

However, Trump himself has repeatedly stated that he would like to speak with Mueller about the ongoing investigation.

"I'm looking forward to it, actually," Trump told reporters at the White House last month, though adding: "subject to my lawyers and all of that."

The president said he would even testify under oath. While Mueller's questioning would not be under oath, it is a crime to lie to federal investigators.

The New York Times cited four people briefed on the matter as saying the president's lawyers are concerned that he could be charged with lying to investigators, as he has previously made false statements and contradicted himself.

The sources said lawyer John Dowd, his deputy Jay Sekulow, long time personal lawyer Marc Kasowitz and many West Wing advisers want to resist the interview request, claiming Mueller lacks the legal standing on some of the issues he is investigating.

However, a refusal could lead Mueller to issue a subpoena for the president to testify before a grand jury, with a court fight that would be decided by the US Supreme Court.

It could also trigger accusations that Trump is hiding information from the public, a painful distraction for Republicans seeking office in November's mid-term elections.