Democrat senator Dick Durbin has said a declassified memo released by the US Congress "does not" vindicate Donald Trump in the investigation into possible collusion with Russia during his presidential campaign.

Speaking to CNN, Durbin said: "The fact that the Republicans in the House refuse to allow a minority report, the Democratic response to their memo, is an indication that they're just bound and determined to continue to find ways to absolve this president from any responsibility."

Earlier this week, the US Congress released a memo, otherwise known as the Nunes memo, that accuses the FBI of abusing its power in its investigations into Trump's presidential campaign.

The four-page memo, with a cover letter from the White House counsel, claims that the FBI omitted information in its application for a wiretap on Trump advisor Carter Page.

"If House Republicans believe they've set the stage for the president to end this investigation, they're basically saying that one man is above the law," Durbin added.

"No one, including the president, is above the law."

Trump and Republicans have said the memo, which was written by Republicans, is proof that the Justice Department's investigation into possible collusion with Russia is biased against the president.

On Saturday, Trump took to Twitter to claim the memo "totally vindicates" him.

"This memo totally vindicates "Trump" in probe. But the Russian Witch Hunt goes on and on," he wrote.

"Their was no Collusion and there was no Obstruction (the word now used because, after one year of looking endlessly and finding NOTHING, collusion is dead). This is an American disgrace!"

Democrats and some Republicans have criticised the memo as containing little evidence of actual wrongdoing by the FBI.

On Saturday, NBC News obtained a response to the memo from Democrat politician Jerry Nadler, which was circulated to all House Democrats.

In the analysis of the memo, Nadler suggests the document serves only to protect Trump amid the Russia investigation.

"Until now, we could only really accuse House Republicans of ignoring the President's open attempts to block the Russia investigation," he writes.

"But with the release of the Nunes memo... We can only conclude that House Republicans are complicit in the effort to help the President avoid accountability for his actions and the actions of his campaign."