Four Democrats in the Senate on Saturday sent a letter to Attorney General Loretta Lynch and FBI Director James Comey requesting a range of disclosures in the wake of Comey's Friday announcement about newly discovered emails possibly pertaining to Hillary Clinton's use of a private server. 

The letter asks for "more detailed information about the investigative steps being taken, the number of emails involved, and what is being done to determine how many of the emails are duplicative of those already reviewed."

Sen. Patrick Leahy, Sen. Dianne Feinstein, Sen. Benjamin Cardin and Sen. Thomas Carper signed the letter and gave Comey and Lynch a deadline of Monday to respond.

Calling Comey's letter from Friday "troubling," and noting that they are aware of the warning given by the Justice Department to the FBI regarding Comey's actions on Friday, the senators also write that his letter to Congressional Republicans breaks with the longstanding tradition of the FBI and Department of Justice proceeding cautiously in the days leading up to an election. 

"Director Comey's letter has been misunderstood. It is already being used for political purposes, creating a misleading impression regarding the FBI's intent and actions," the senators wrote, calling on federal officials to dispel any misleading impressions and clarify what significance any of the new emails have to the previous investigation of Sec. Clinton. 

The Justice Department advised Comey against telling Congress about newly discovered emails possibly "pertinent” to the agency’s investigation into Clinton’s server, with GOP rival Donald Trump on Saturday suggesting a cover-up.

“That’s because the Justice Department is trying so hard to protect Hillary,” Trump said at a rally in battleground Colorado. “This is what we mean when we call it a rigged system. … She is so guilty.”

Comey said in a letter that was made public Friday that the FBI discovered the emails while pursuing a case related to the husband of top Clinton aide Huma Abedin -- disgraced former New York Democratic Rep. Anthony Weiner, who was allegedly sexting a 15-year-old girl on a laptop he shared with his wife. 

A government source confirmed Saturday to Fox News that the Justice Department concluded the letter to Congress would be inconsistent with agency policy against investigations that could impact an election or help a particular candidate.

Comey purportedly made the decision to send the letter to Capitol Hill committee leaders independently of the Justice Department.

The FBI this summer concluded its rough 2-year-long investigation into Clinton’s use of a private server while secretary of state.

Comey said at the time that some of the emails contained classified information and that Clinton was “extremely careless” in her actions. However, the agency didn’t find enough evidence to recommend criminal charges to the Justice Department.

Clinton, who in most major polls leads Trump by about 5 percentage points, on Saturday repeated her call for Comey to provide more details, saying “explain everything right away, put it all out on the table.”

“If you're like me, you probably have a few questions about it,” Clinton said at a rally in Daytona Beach, Florida. “It is pretty strange to put something like that out with such little information right before an election. In fact, it's not just strange, it's unprecedented and deeply troubling because voters deserve to get full and complete facts.”

She also accused Trump of “making up lies” about the issue and “doing his best to confuse, mislead and discourage the American people.”

Late Friday in Iowa, Clinton called on Comey to release the "full and complete facts" about the FBI review. In a speech Friday in Daytona Beach, Floriday, Clinton called Comey's release of the letter "unprecedented" and repeated her demand for more specifics.

On a conference call Saturday with reporters, Clinton campaign officials said the FBI has given no indication that the cache of recently discovered emails are even about the candidate

Campaign chairman John Podesta said Comey's information is "long on innuendo" and "short on facts." He also said there's "no evidence of wrongdoing. No charge of wrongdoing. No indication this is even about Hillary."

Podesta made the argument despite Comey saying the newly discovered emails are possibly "pertinent" to the larger Clinton email investigation.

Trump made a total of three campaign stop Saturday, with Election Day just 10 days away.

In Colorado, where Trump trails Clinton by single digits, he suggested the effort to protect Clinton went all the way to Attorney General Loretta Lynch, the Obama administration’s top law enforcement officer.

In late-June, Clinton’s husband, former President Bill Clinton, got off his plane in Phoenix to talk with Lynch, whose plane was on the same tarmac.

Lynch has said they talked about golf, travel and grandchildren. But the private meeting occurred days before the FBI interviewed Clinton, then closed the case.  

“I’ve had a plane for a long time, and I’ve never had anybody walk off the runway and into my plane,” Trump said in Colorado.

The Clinton campaign late Saturday argued Deputy Attorney General Sally Yates also objected to Comey sending the letter.

Trump on Saturday also campaigned in North Carolina and Arizona, where he is in tight races with Clinton to win the White House.

Clinton on Saturday also campaigned in Miami, Florida, another essentially must-win state for both candidates.

The Associated Press contributed to this report.