"The Mueller investigation has already uncovered serious crimes committed by the President's closest associates", the signatories said in the letter.
While the full scope of Mueller's investigation remains classified, Attorney General Rod Rosenstein appointed him in May 2017 to investigate allegations of collusion between Trump campaign associates and Russian Federation.
The Justice Department said earlier this week that Whitaker would consult with ethics officials about "matters that may warrant recusal".
The President's comments come as his legal team is reportedly wrapping up answers to written questions submitted by Mueller's investigators.
Meghan Markle's Personal Assistant Just Quit
According to Hello!, although the reason for Melissa's resignation is unknown, it is likely due to the hectic nature of the job. During the event, the Queen watched from the balcony of the Foreign and Commonwealth Office building, as she did past year .
Russia's alleged meddling in elections in the United States and France, as well as Brexit referendum in the United Kingdom, cost less than one US F-35 combat jet, Vice Chairman of the US Senate Select Intelligence Committee Mark Warner said.
Top Senate Democrat Chuck Schumer has said that if Whitaker refuses to recuse himself from the probe, as Sessions had done, Democrats will seek to attach legislation protecting Mueller to a must-pass spending bill that will be up for consideration in the coming weeks.
Dianne Feinstein of California, Jerry Nadler of NY, and Adam Schiff of California, wrote in a statement released Thursday that the Office of Legal Counsel's argument justifying Whitaker's appointment "is fatally flawed".
More Evidence Emerges of Soft iPhone Sales
Based on Lumentum forecast, analysts have deduced that there is an 18 to 20 million reduction in iPhone orders from Apple . The analyst in his research note has also said that customers expect dual-cameras and a narrower bezel at this price point.
"This will embolden the future use of temporary appointments for illegitimate purposes".
The Justice Department's opinion concluded that Whitaker's appointment was allowed under a 1998 law called the Federal Vacancies Reform Act.
Trump has repeatedly attacked the investigation, which has led to criminal charges against several former Trump aides.
He said that the power of the Justice Department can not "go to a political hack" - adding that the way to absolve a political appointment of the suspicion of being a "hack" nomination is to have their candidacy confirmed by the U.S. Senate.
The Justice Department also cited an 1866 example of an acting attorney general being appointed without Senate confirmation, which Democrats pounced on.
Israel defence minister urges early elections after resigning
Israel responded with 160 airstrikes on military targets in Gaza. "But in the security of Israel, more is hidden than known". Haniyeh further stressed that Hamas had "achieved a military victory against this odious occupier in less than a week".