National Security Agency (NSA) Director Mike Rogers is frustrated that he has not yet convinced President Trump that U.S. intelligence indicates Russia interfered in the 2016 presidential election, CNN reported Wednesday.

Rogers vented frustration over his fruitless efforts to lawmakers during a recent closed-door briefing on Capitol Hill, a congressional source familiar with the meeting told the news network.

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The NSA director also reportedly said the White House lacked focus about the continued threat of the Kremlin's cyber efforts, especially regarding voting systems in the U.S., another congressional source said.

The intelligence community continues to brief the president on new information on Russia's election involvement as it comes to light.

An intelligence official told CNN that while Trump does not seem less engaged when being briefed on the matter, he has expressed frustration outside of the briefings that too much attention is being paid to the ongoing probe into Russia's interference in the election.

Russia, as well as other countries such as China, Iran and North Korea are considered potential threats by U.S. intelligence.

CNN reported that other top administration officials have also tried to emphasize the importance of a foreign nation attempting to meddle in the U.S. elections.

The president has taken to social media to criticize former President Barack Obama Barack Hussein ObamaDemocrats ramp up pressure on Lieberman to drop out of Georgia Senate race The Hill's Campaign Report: Biden on Trump: 'He'll leave' l GOP laywers brush off Trump's election remarks l Obama's endorsements Trump pledges to make Juneteenth a federal holiday, designate KKK a terrorist group in pitch to Black voters MORE after a bombshell report by The Washington Post revealed his predecessor was briefed about Russia's activities in August 2016 and was slow to respond.

"I just heard today for the first time that Obama knew about Russia a long time before the election, and he did nothing about it," Trump told Fox News in an interview that aired Sunday. "To me -- in other words -- the question is, if he had the information, why didn't he do something about it? He should have done something about it."

Trump has also repeatedly called the ongoing probe into Russia and possible ties between the Kremlin and his campaign a "witch hunt."