Story highlights There is a "general fear that the White House will try to interfere with the investigation" of Russia, one FBI source says

The startling way Comey was fired infuriated and unified many agents

(CNN) Some FBI investigators are worried the Trump administration could try to interfere with probes, including on Russia, by shifting resources and priorities away from counterintelligence investigations, FBI sources tell CNN.

There is a "general fear that the White House will try to interfere with the investigation" into Russian election meddling, one FBI source said. "The first target will be the leak investigation, and then, long term, if Donald Trump appoints some crony, that could make the whole Russia investigation go away."

Acting FBI Director Andrew McCabe told senators Thursday, "I strongly believe that the Russian investigation is adequately resourced."

One source said Deputy Attorney General Rod Rosenstein isn't inclined to make a change unless the FBI investigation appears to be imperiled, and at this point, FBI officials are confident that the investigation is moving ahead, despite Comey's abrupt firing. The investigation is overseen by Dana Boente, the US attorney in Alexandria, Va., who now also serves as the head of national security prosecutions at Justice Department headquarters.

Meanwhile, current and former agents said the startling way that Comey was fired -- he learned the news from television reports while on a trip to Los Angeles -- infuriated and unified many agents regardless of how they felt about the former FBI director personally.

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