Protesters gathered in major cities around the U.S. on Thursday over President TrumpDonald John TrumpAlaska Republican Party cancels 2020 primary Ukrainian official denies Trump pressured president Trump goes after New York Times, Washington Post: 'They have gone totally CRAZY!!!!' MORE's firing of Attorney General Jeff SessionsJefferson (Jeff) Beauregard SessionsTrump reignites court fight with Ninth Circuit pick Democrats press Nadler to hold Lewandowski in contempt Pelosi: Lewandowski should have been held in contempt 'right then and there' MORE, rallying in support of Robert MuellerRobert (Bob) Swan MuellerLewandowski says Mueller report was 'very clear' in proving 'there was no obstruction,' despite having 'never' read it Fox's Cavuto roasts Trump over criticism of network Mueller report fades from political conversation MORE, the special counsel in charge of the investigation into Russian election meddling.

The hashtag "#ProtectMueller" was the top trending term on Twitter in the U.S. Thursday night as demonstrators gathered in Washington, D.C., New York and Boston, as well as other cities around the country.

A list of events hosted by the activist group Public Citizen listed dozens of events in smaller cities in nearly every state Thursday night as demonstrators protested what many thought to be an effort by the president to begin shutting down the Russia investigation.

ADVERTISEMENT

Sessions is set to be replaced by Matthew Whitaker as acting attorney general pending a permanent replacement to be confirmed by the Senate. Whitaker in the past has been a vocal opponent of the Mueller investigation.

Photos of events posted on Twitter showed hundreds of protesters gathered in various locations holding signs reading "Protect Mueller" and "Nobody is above the law."

Protests Thursday came hours after Arizona Sen. Jeff FlakeJeffrey (Jeff) Lane FlakeFlake donates to Democratic sheriff being challenged by Arpaio in Arizona The Hill's Morning Report - Trump says US-China trade talks to resume, hails potential trade with Japan, UK Joe Arpaio to run for Maricopa County sheriff in 2020  MORE (R), himself a frequent critic of the president, vowed to force a vote in the Senate on bill that would codify Justice Department regulations stating that only a senior DOJ official can fire the special counsel.

Trump has been critical of the Mueller investigation for months, deeming the probe which has ensnared several former members of his campaign in criminal charges as a "witch hunt" led by "angry Democrats."

Sessions had been expected to exit the Trump administration for months, and turned in his resignation to Trump on Wednesday just hours after Democrats retook the House in Tuesday's midterm elections.