WASHINGTON – The top Democrat on the Senate Intelligence Committee warned President Trump on Wednesday that any effort to dismiss Russia special counsel Robert Mueller would amount to "a gross abuse of power."

Speaking from the Senate floor, Virginia Sen. Mark Warner noted there has been "a growing chorus of irresponsible and reckless voices" from the Republican House to conservative media outlets who have called on the president to shutter Mueller's inquiry into Russia's interference in the 2016 election and possible collusion with Trump associates.

"I believe it is up to every member of this institution, Republican or Democrat, to make a clear and unambiguous statement that any attempt by this president to remove special counsel Mueller from his position or to pardon key witnesses in an effort to shield them from accountability... would be a gross abuse of power," Warner said. "These are red lines, and we simply cannot allow them to be crossed."

As recently as Sunday, Trump said he was not planning to dismiss Mueller, even as conservative accusations of political bias intensified after the removal of a senior FBI agent from the inquiry for disparaging Trump in a series of text messages shared with a bureau lawyer.

More:House conservatives ramp up accusations of bias against Trump in Russia probe

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The most vocal criticisms came last week from some Republican members of the House Judiciary Committee who seized on Mueller's dismissal of senior FBI counter-intelligence agent Peter Strzok earlier this summer for variously describing the president as an "idiot" in pre-election communications with colleague Lisa Page.

In the same messages, Strzok expressed a clear preference for Democratic nominee Hillary Clinton.

Warner, whose committee is one of three congressional panels conducting separate Russia inquires, said Mueller's removal of Strzok "only adds to Mr. Mueller's credibility as a fair and independent investigator."

Returning from Camp David on Sunday, Trump told reporters he was not happy with the way the investigation is being handled — and that transition emails were improperly turned over to Mueller's investigators.

"Not looking good. It’s not looking good. It’s quite sad to see that. My people were very upset to see that," Trump said. "A lot of lawyers thought that was pretty sad.”

Trump was responding to a complaint that the General Services Administration had turned over to investigators thousands of pages of emails to and from Trump transition officials. The GSA is responsible for running presidential transitions, and the Trump officials were using government email accounts.

Trump transition lawyer Kory Langhofer complained to congressional committees that the emails should not have been turned over, but the GSA maintains that they were government records.

More:Trump calls investigation into transition emails 'very sad,' but says he won't fire Mueller

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