Washington (CNN) President Donald Trump could have been exposed to "serious national security and counterintelligence risks" if he pressured the leader of Ukraine to investigate former Vice President Joe Biden, a political rival, in a call this summer, the intelligence community's inspector general said.

The explosive charge is among the reasoning cited in Inspector General of the Intelligence Committee Michael Atkinson's report which said the complaint by a whistleblower , which detailed the July 25 call and other moves by the Trump administration regarding Ukraine, amounts to an "urgent concern" and "appears credible" -- two statutory requirements considered as whistleblower allegations progress through review.

"In the ICIG's judgment, alleged conduct by a senior US public official to seek foreign assistance to interfere in or influence a Federal election... would also potentially expose such a US public official (or others acting in concert with the US public official) to serious national security and counterintelligence risks with respect to foreign intelligence services aware of such alleged conduct," Atkinson wrote.

Despite the inspector general's transmitting of the whistleblower's complaint to acting Director of National Intelligence Joseph Maguire along with his finding of "urgent concern" in late August, the complaint was not sent to Congress until this week.

In testimony before the House Intelligence Committee Thursday, Maguire said that he consulted with the White House counsel's office and later the Justice Department's Office of Legal Counsel after receiving the complaint for guidance on how to handle it.

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