Democrats' call to action after Vegas shooting includes plea for 'moral courage' on gun control legislation House Democrats gather on the steps of the Capitol.

 -- Democrats, seething over GOP inaction on gun control, are pushing piecemeal legislation after the deadliest shooting in modern U.S. history in Las Vegas Sunday night.

Rep. John Lewis, D-Ga., the civil rights icon who has led the push for tightening gun control laws in Congress, called on Democrats and Republicans to display "moral courage."

"All of the members of Congress - have courage, be unafraid, do your job, bring common-sense gun control legislation to a vote," Lewis said today on the steps of the U.S. Capitol.

"How many more dead bodies will it take to wake up this Congress?" he thundered. "This must stop, and it must stop now. We were elected to lead."

Former Arizona Rep. Gabby Giffords, who still struggles to speak and walk after being shot in the head in her district in 2011, also implored her former colleagues to act.

"I've seen great courage when my life was on the line. Now is the time to come together," the Democrat said.

Sen. Dianne Feinstein, D-Calif., announced plans to introduce legislation to ban the sale of "bump stocks," a device that allows semi-automatic firearms to function like an automatic weapon. A modified bump stock rifle was discovered in the hotel room of the Las Vegas gunman who killed 59 people and wounded more than 500 people.

“A ban on bump fire stocks was included in my 2013 assault weapons bill, and I’m looking at how best to proceed with legislation to finally close this loophole," she said in a statement. "This is the least we should do in the wake of the deadliest mass shooting in U.S. history. It should be our highest priority.”

Republican leaders have pushed back on Democrats' calls for tightening gun control legislation after the shooting, calling the demands premature.

"I think it's particularly inappropriate to politicize an event like this," Senate Majority Leader Mitch McConnell, R-Ky., said Tuesday. "The investigation's not even been completed."

"Let's wait," said Rep. Peter King, R-N.Y., who has repeatedly introduced bipartisan legislation to toughen background checks and expand them to all commercial firearm sales, including gun show and internet purchases. "To me, it's really wrong to jump out and politicize a tragedy."

House Speaker Paul Ryan, R-Wis., pointed to mental health legislation passed by Congress in December when asked how Congress could address the safety of Americans after the Las Vegas shooting.

"That law is now being implemented, so I think it's important that as we see the dust settle and we see what was behind some of these tragedies, that mental health reform is a critical ingredient to making sure that we can try to prevent some of these things from happening in the past,” he said.

Democrats have pushed gun control legislation for years after mass shootings, with no success. In 2013, the Senate voted down a proposal to expand background checks in the wake of the Sandy Hook massacre.

In 2015, the Senate rejected two proposals to prevent terror suspects from purchasing firearms and expand background checks after the shooting at a holiday party in San Bernardino, Calif. Other proposals, including one to limit high-capacity magazines, have not advanced.

"The best way to honor victims of gun violence in our country is to take action," Rep. Katherine Clark, D-Mass., said in an interview with ABC News after walking off the House floor during a moment of silence for Las Vegas to protest congressional inaction. "A moment of silence is all that we get from the leadership of this House."

Rep. Jim Clyburn, D-S.C., the assistant Democratic leader who represents Charleston, told ABC News he took a knee on the House floor Tuesday night.

"We’re not addressing what we had with the nine in Charleston," he said, referring to the 2015 church shooting in that city that killed nine people, and the fact that the shooter cleared a federal background check and was able to purchase a gun.

"If it’s not illegal for me ... to make a semi-automatic weapon automatic, what are we doing here?"

Lewis, the civil rights leader who led the gun control sit-in on the House floor last year after the Pulse nightclub shooting in Orlando, approached Speaker Ryan on the House floor Tuesday night, seeking his cooperation for today’s demonstration. Ryan declined, according to Democrats.

A Ryan spokesman had no comment on the private conversation.

Speaking on the Senate floor Tuesday morning, Senate Minority Leader Chuck Schumer, D-N.Y., called on President Donald Trump to bridge the divide between Democrats and Republicans on gun control.

"He should tell members of his party that it’s time to work addressing this epidemic," Schumer said.

As a businessman, Trump was supportive of President Barack Obama's calls to tighten gun control laws after Sandy Hook, but embraced the pro-gun community and its advocates during the 2016 presidential campaign.