WASHINGTON (Reuters) - A classified memo by congressional Democrats related to investigations of Russian influence in the 2016 U.S. presidential election is “very political and long” and must be “heavily redacted” before it could be released, President Donald Trump said on Twitter on Saturday.

The release of the memo was blocked by Trump on Friday, kicking off a new skirmish between Democrats and the White House. Written by Democrats on the House Intelligence Committee, is was intended to rebut a Republican document made public last week with Trump’s consent.

The memo by committee Republicans claimed bias against Trump by the Federal Bureau of Investigation and Justice Department in the federal investigation of Russia and the 2016 U.S. election.

The Intelligence Committee had voted unanimously on Monday to release the document drafted by the panel’s Democrats, contingent on the Republican president agreeing.

“The Democrats sent a very political and long response memo which they knew, because of sources and methods (and more), would have to be heavily redacted, whereupon they would blame the White House for lack of transparency,” Trump tweeted. “Told them to re-do and send back in proper form!”

Trump’s decision to block the release of the memo infuriated Democrats, who said it showed a double standard on transparency on the part of the Republican president.

Representative Adam Schiff, the senior Democrat on the Intelligence Committee, said in a statement on Saturday that he will review redactions recommended by the FBI and Justice Department.

“We hope this matter can be quickly resolved so the committee can return to its charge - fully investigating the Russian interference in our election and the role of the Trump campaign, and what steps need to be taken to protect against foreign interference in the next election, now only months away,” Schiff said.

He was referring to November’s U.S. elections in which all 435 seats in the U.S. House of Representatives and 34 of 100 Senate seats are in play. Currently, Republicans hold majorities in both chambers. Democrats hope Trump’s low popularity in public opinion polls will help them win majorities, and some analysts give them a good chance.

House Intelligence Committee Chairman Devin Nunes, in a statement posted on Twitter, called on Democrats to accept the Justice Department’s recommendations and “make the appropriate technical changes and redactions” so that the memo can be declassified as soon as possible.

Trump on Feb. 2 allowed the release of the Republican document with no redactions, even though the Justice Department and FBI argued against making it public. The FBI expressed “grave concerns about material omissions of fact” in the Republic memo.

Democrats said it mischaracterized highly sensitive classified information and was intended to discredit special counsel Robert Mueller’s investigation of potential collusion between Trump’s 2016 campaign and Russia.

Trump repeatedly has denied any such collusion.

Late on Friday, Senator Dianne Feinstein, a senior Democrat on the Senate Intelligence Committee, accused Trump of “hypocrisy at its worst” in blocking, at least for now, release of the House Democrats’ memo.

“Any minor redactions should be made as quickly as possible and the memo should be released,” she said.