Image copyright EPA Image caption Mr Trump earlier overruled FBI objections to release a Republican document

US President Donald Trump has blocked the release of a Democratic rebuttal of a Republican memo alleging the FBI's Russia inquiry is biased against him.

In a tweet, he said he had told the Democrats "to re-do and send back in proper form!"

The White House said Mr Trump could not declassify the Democrats' memo because of "sensitive passages" that created "concerns for national security".

A congressional panel had voted unanimously to make it public.

House Democratic leader Nancy Pelosi accused Mr Trump of trying to hide the truth about "the Trump-Russia scandal".

But Mr Trump said the Democrats had included material that they knew would have to be redacted in order to "blame the White House for lack of transparency".

Democrats say their memo corrects errors and omissions in the Republican memo, which Mr Trump approved.

He defied warnings from the FBI (Federal Bureau of Investigation) when he allowed it to be released at the beginning of the month.

The document alleges the agency abused its power by investigating a Trump adviser as part of its inquiry into allegations of Russian interference in the 2016 presidential election.

How does the White House justify blocking the Democratic response?

White House Counsel Don McGahn said the president was "inclined" to approve the memorandum's release but was "unable to do so at this time" because it contained "numerous properly classified and especially sensitive passages".

He gave the explanation in a letter to the House Intelligence Committee's Republican chairman, Devin Nunes, who had overseen the original memo which caused such controversy.

Attached was a joint letter from Deputy Attorney General Rod Rosenstein and FBI Director Christopher Wray which refers to unspecified information in the Democratic memo for which there are "significant" national security or law enforcement concerns.

Both documents were obtained and published by the Vox website.

Mr McGahn added that the White House was ready to review any revised version of the Democratic memo.

But the Nunes committee deemed the memo safe to publish, right?

Yes. The House Intelligence Committee, which is led by Mr Trump's Republicans, voted unanimously on Monday to release the Democrats' 10-page report.

That left it up to President Trump to decide whether or not to clear it.

Ms Pelosi issued a statement declaring: "The president's decision to block the Democratic memo from release is part of a dangerous and desperate pattern of cover-up on the part of the president.

"Clearly, the president has something to hide."

The senior Democrat on the committee, Adam Schiff, accused Mr Trump on Twitter of double standards, for not blocking the original Republican memo despite the pleas of the justice department and FBI.

He added that his party was willing to consider taking out certain parts of its memo.

Image copyright EPA Image caption Mr Schiff said changes could be made

What is the gist of the memo Mr Trump is blocking?

Democrats who worked on the 10-page document say it rebuffs allegations in the Republican memo published on 2 February.

Media playback is unsupported on your device Media caption All you need to know about the Trump-Russia investigation

The Republican memo, which was four pages long, accuses US investigators of using flawed evidence to obtain a warrant for spying on former Trump aide Carter Page.

Mr Page has denied acting as an intermediary between Russian officials and the Trump campaign at the 2016 election.

Media playback is unsupported on your device Media caption President Trump said he welcomed being quizzed by Mr Mueller

Democrats argue the Nunes memo is an attempt to undermine the federal inquiry into allegations that the Trump campaign colluded with Russia.

The president has said he is willing to be interviewed under oath by the FBI.

Russia-Trump: Who's who in the drama to end all dramas?