More than 60 Senate and House Democrats are pressing President Joe Biden to leverage "the full power of the executive branch" to combat gun violence in a new letter calling for a number of immediate actions to make the process of purchasing firearms safer and hold firearms dealers accountable.

The letter, signed by a wide coalition of congressional Democrats, has the backing of Senate leadership, including Majority Leader Chuck Schumer and Democratic whip Dick Durbin. The letter outlines steps the Biden administration could take without congressional approval -- underscoring that there is no expectation Congress will pass gun-related legislation anytime soon amid deep partisan divides over the issue.

With more than 400 mass shootings already this year, 2023 is set to be one of the deadliest year for mass shootings in American history.

"With Republicans in Congress refusing to act, the American people are relying on your Administration to ensure that they can move through their daily lives without fear of firearms on the streets, in public establishments, and in their homes," the lawmakers wrote in the letter sent to Biden Monday.

The lawmakers, led by Sens. Elizabeth Warren of Massachusetts, along with Raphael Warnock of Georgia and Reps. Diana DeGette of Colorado and Abigail Spanberger of Virginia and others, want to see Biden leverage the federal government's status as a major purchaser of firearms to develop public safety practices for vendors in order to be awarded government contracts.

The proposals put forward would incentivize gun manufacturers to decline to sell military-grade weapons to civilians and only sell to responsible dealers who refuse to proceed with a sale without a completed background check. Some of the most urgent actions proposed by the lawmakers include implementing a code of conduct for manufacturers for procuring taxpayer-funded firearms.

"Codes of conduct could be developed by each agency in consultation with the White House and could contain various public safety practices that firearm vendors must follow in order to be awarded government contracts. ... The federal government has the authority to impose conditions on the award of federal contracts under the Federal Property and Administrative Services Act, and your Administration has leveraged that authority on multiple occasions," the lawmakers wrote.

They also encouraged the administration to direct the Bureau of Alcohol, Tobacco, Firearms and Explosives to review the lists of firearms that are imported under the "sporting purposes" exception, pointing out that roughly one fourth of rifles in the US are imported. The exception, according to the letter, has not been reviewed in 20 years for rifles and 10 years for shotguns, and is one of the primary exemptions used for importing firearms.

Additionally, the lawmakers urged the Federal Trade Commission to issue a policy statement establishing that advertisements will be found unfair and/or deceptive when they claim that gun ownership increases the safety of household residents. DeGette, who until last year represented the district where the Columbine massacre took place, urged the FTC to aggressively go after advertisements.

"The FTC has the ability to determine that a practice is unfair and deceptive. And in this situation, when these gun sellers are using fear mongering, and they're capitalizing on anxious buyers through this messaging that falsely says firearm ownership increases residents' physical safety that's unfair and deceptive because it's not true," DeGette told CNN.

As a former federal agent who had carried a gun daily and the mother of three school-aged children, Spanberger told CNN that she hopes the president understands the urgency, saying, "I mean, he better. ... I would hope so."

The administration is currently reviewing the letter, a White House official told CNN.

"President Biden will continue to do everything in his power to keep the American people safe by fully implementing the historic Bipartisan Safer Communities Act he signed last year, and by maximizing the record number of executive actions he has taken as President to combat gun violence," White House spokesperson Olivia Dalton told CNN in a statement. "Importantly, he will also continue to call on Congress to pass universal background checks legislation, as well as other commonsense legislation to ban assault weapons and high-capacity magazines, require safe storage of guns, and end immunity from liability for gun manufacturers."

The lawmakers acknowledged in the letter what they called "critical" steps the administration has taken through executive actions, including a major March executive order to move the United States "as close to universal background checks as possible without additional legislation."

According to a May CNN poll conducted by SSRS, most Americans continue to say gun control laws should be stricter, with broad support for preventing people under the age of 21 from buying any type of gun. Sixty-four percent say they favor stricter gun control laws, with 36% opposed.

Democrats on the letter eye their stated measures as opportunities to expand on executive actions already taken by the administration, sending a signal to Biden that "Democrats in Congress have his back to do more," Warren told CNN in a statement. "Americans want to see the President use every tool at his disposal to prevent gun violence, including limiting assault weapon sales and holding firearm dealers accountable."

Last year, Congress failed to get the The Assault Weapons Ban Act, which would ban the sale of certain semi-automatic weapons including AR-15s, through Senate after clearing the Democratic-controlled House.

In March, a day after a mass shooting left six dead in Nashville, Biden told reporters, "I have gone the full extent of my executive authority to do, on my own, anything about guns." That comment, which frustrated many in his own party at the time, underscores why lawmakers feel the need to urge Biden on specifics.

"I know he understands the urgency. I think maybe he wasn't thinking about these additional items that he could take action on," DeGette told CNN.

Spanberger said that lawmakers are "still trying to move forward on the legislative front, but recognizing that that is not going to be the greatest avenue of progress, we wanted to make clear to President Biden and the administration there are steps they could take to just bring greater safety to the process of purchasing firearms."

"We are a nation living in fear of gun violence," Warnock said in a statement to CNN. "Some seem to think that this is the price we have to pay for freedom -- I reject that. It's a strange kind of freedom that causes our families and neighbors to fear for their safety in schools, malls, movie theaters, and houses of worship. We can do better than this."