Washington (CNN) Senate Judiciary Committee Chairman Chuck Grassley said Wednesday he hopes President Donald Trump does not try to direct him to "take control" of the Russia probe.

Grassley, the Iowa Republican who leads Senate oversight of the Justice Department, was responding to a tweet from Trump where the President called on his party to "take control" of the probe into potential coordination between his associates and Russia, insisting it is the "single greatest" witch hunt in US history.

The single greatest Witch Hunt in American history continues. There was no collusion, everybody including the Dems knows there was no collusion, & yet on and on it goes. Russia & the world is laughing at the stupidity they are witnessing. Republicans should finally take control! — Donald J. Trump (@realDonaldTrump) January 10, 2018

Asked by CNN's Manu Raju about the tweet, Grassley said, "I don't know what the President has in mind, and I don't think I better comment until I have a discussion with the President on that point, and I don't intend to have a discussion with the President on that point, and I hope he doesn't call me and tell me the same thing that you said he said."

Shortly before the "control" tweet, Trump sent one labeling California Democratic Sen. Dianne Feinstein as "sneaky" and slammed her for releasing testimony Tuesday from the August questioning of the co-founder of Fusion GPS, the company that hired the author of the dossier of allegations about Trump and Russia.

The fact that Sneaky Dianne Feinstein, who has on numerous occasions stated that collusion between Trump/Russia has not been found, would release testimony in such an underhanded and possibly illegal way, totally without authorization, is a disgrace. Must have tough Primary! — Donald J. Trump (@realDonaldTrump) January 10, 2018

Grassley told CNN he opposed Feinstein's decision and contended the release would make voluntary testimony from future witnesses more difficult. Asked if that meant Trump son-in-law Jared Kushner was no longer of interest to the committee, Grassley said, "no, not at all."

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