The Trump administration tried to "lock down" the transcript of the US president's controversial phone call to Ukraine's leader, according to a whistleblower's report.
The nine-page document was released ahead of evidence to House of Representatives investigators from Joseph Maguire, the acting director of national intelligence.
In the 25 July phone call, Mr Trump asked Ukraine president Volodymyr Zelensky for “a favour” to investigate corruption claims involving the son of Joe Biden, the leading Democratic presidential hopeful.
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The whistleblower’s document, with its precise detail and clear narrative, is likely to accelerate the impeachment process and put more pressure on Mr Trump to rebut its core contentions and on his fellow Republicans to defend him.
It will also complicate the president's effort to characterise the findings as those of a lone partisan out to undermine him. Mr Trump insisted afresh that it is all political.
After the complaint was released, he immediately tweeted in capital letters: "The Democrats are trying to destroy the Republican Party and all that it stands for. Stick together, play their game and fight hard Republicans. Our country is at stake."
The White House released what it called “a rough” transcript of that call on Wednesday.
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While Congress' timeline is unclear, the impeachment inquiry may well run simultaneously with the Democratic Party's primary election calendar. The first primary votes are scheduled in early February.
House Democrats who are now mulling Mr Trump's impeachment are hoping Joseph Maguire will explain why he withheld it from Congress for weeks.