Sessions, a Republican and former Alabama senator, has been the focus of public attacks by Trump, who criticized him for recusing himself from the Russian Federation investigation because of his role on the Trump campaign team before becoming attorney general.
Rep. Jerry Nadler (D-N.Y.), who will oversee the committee now that the Democratic Party has taken control of the House, cautioned the president that he will now face far more oversight from lawmakers and warned that Sessions' firing and subsequent appointment of loyalist Matthew Whitaker to serve as acting attorney generalhas thrown the nation into a "constitutionally perilous moment".
Republican Senator Lamar Alexander of Tennessee said Mueller's probe will continue to its end "because no new attorney general can be can be confirmed who will stop that investigation".
Meanwhile, President Donald Trump's legal team has begun working with the president to craft responses to questions from Mueller's team as part of their investigation, sources close to Trump told ABC.
In the House of Representatives, the senior Democrat on the Judiciary Committee - which Democrats will control from January - called for an investigation of Sessions' firing.
The sacking followed months of Mr Trump criticising Mr Sessions, mainly for his decision to step aside from the Russian Federation inquiry in March 2017.
The Washington protest is set to take place in front of the White House.
That is true with the Mueller investigation, and I think in terms of the prior comments of Mr. Whitaker, they need to be examined, and then there's a process within the Justice Department, with consultation with the ethics officials, to see whether or not it requires recusals.
If Mr Whitaker made a decision to fire Mueller, he would need to inform the special counsel in writing of the specific reason for his termination.
Whitaker now becomes Mueller's new boss and judging by past statements he will be sympathetic towards Trump.
Trump's running commentary criticizing Sessions and the Justice Department injected more turmoil into an agency that was still reeling from the president's firing of FBI Director James Comey in May 2017. Days after ousting Comey, Trump said he was thinking of "this Russian Federation thing" when he chose to dismiss him.
A political analyst in the state predicted Sessions would run for the seat. A federal judge has ordered Kobach, Kansas' top elections official, to produce by Thursday, April 6, 2017, a plan on homeland security issues that he brought to the meeting with Trump.
Sessions took the lead in imposing Trump's travel ban targeting a number of mostly Muslim nations, canceling the so-called Dreamer program that let the children of undocumented immigrants remain in the US and forcing the separation of migrant families as part of a border crossing crackdown.