The U.S. House Intelligence panel on Thursday released the whistleblower complaint concerning a phone call between U.S. President Donald Trump and Ukrainian President Volodymyr Zelensky. 

The whistleblower said Trump used his office to solicit Ukraine's interference in the 2020 election to advance his personal political interests, risking U.S. national security.

"I am deeply concerned that the actions described below constitute 'a serious or flagrant problem, abuse, or violation of law or executive order' that 'does not include differences of opinion concerning public policy matters,' consistent with the definition of an 'urgent concern'," the report said. 

"In the days following the phone call, I learned from multiple U.S. officials that senior White House officials had intervened to 'lock down' all records of the phone call," the whistleblower said.  

"White House officials told me that they were 'directed' by White House lawyers to remove the electronic transcript from the computer system in which such transcripts are typically stored for coordination, finalization, and distribution to Cabinet-level officials," the whistleblower added.

The report was made public shortly before the scheduled start of a House of Representatives Intelligence Committee hearing at which acting Director of National Intelligence, Joseph Maguire, is to testify after refusing for weeks to share the report with Congress.

The report was declassified and released by the committee after weeks of controversy over the matter, which led to House Speaker Nancy Pelosi launching a formal impeachment inquiry into the Republican president.

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Shortly before the hearing, the intelligence committee's chairman, Democratic Representative Adam Schiff, announced that it had received the declassified complaint and released it to the public. 

"This complaint should never have been withheld from Congress. It exposed serious wrongdoing, and was found both urgent and credible by the Inspector General," Schiff said in a statement.

Trump has denied wrongdoing and accused Democrats of trying to destroy him politically.

The whistleblower complaint concerns a July 25 telephone call in which Trump pressed Ukrainian President Volodymyr Zelensky to investigate Joe Biden, the 2020 Democratic presidential front-runner, and his son Hunter, who had worked for a company drilling for gas in Ukraine. 

Reports about the call prompted Democrats on Tuesday to launch a formal impeachment inquiry into Trump, accusing him of seeking foreign help to smear Biden, the former U.S. vice president. There is no evidence the Bidens acted improperly.