WATCH: Democratic senators, advocates urge gun reforms after Uvalde school massacre

The mass shooting at Robb Elementary School in Uvalde, Texas brought gun control advocates to Washington Thursday to demand lawmakers pass substantial gun violence legislation.

Watch the event in the player above.

Grassroots advocate groups, Moms Demand Action and Everytown for Gun Safety rallied at the Capitol along with some Democrat senators to denounce the inaction of Republican senators to move forward with gun control measures.

In the wake of the massacre – the nation’s deadliest school shooting since Newtown, Connecticut, a decade ago, rally participants questioned how Republican senators could not be “outraged” at the violence.

Ade Osadolor-Hernandez, a national advisory board member for Students Demand Action, said “We need more than thoughts and prayers. We demand action from our lawmakers.”

While adding, “the culture is shifting and the narrative changing. So, let’s find empowerment through actions. Let’s learn together and let’s fight together because we can. And we will demand action for change.”

READ MORE: We asked every senator what action should be taken on guns. Here’s what they said

California Senator Alex Padilla said, “this is personal”, reflecting on his school-age children who he said could be victims of gun violence like those in Uvalde. He voiced his emotions and questions how his Republican colleagues could not be “outraged” at the killings.

Democrats’ first attempt at responding to the back-to-back mass shootings in Buffalo and Uvalde, Texas, has failed in the Senate.

Republicans on Thursday blocked debate on a domestic terrorism bill that would have opened debate on domestic terrorism, hate crimes and gun policy.

The final vote was 47-47, short of the 60 needed to take up the bill.

Rejection of the bill, just two days after the mass shooting at a Texas elementary school that killed 19 children and two teachers, brought into sharp relief Congress’ persistent failure to pass legislation to curb the nation’s epidemic of gun violence.

Schumer said he will give bipartisan negotiations in the Senate about two weeks, while Congress is away for a break, to try to forge a compromise bill that could pass the 50-50 Senate, where 60 votes will be needed to overcome a filibuster.

A small, bipartisan group of senators who have for years sought to negotiate legislation on guns met Thursday afternoon for the second time searching for any compromise that could win approval in Congress.

READ MORE: We asked every senator what action should be taken on guns. Here’s what they said

They narrowed to three topics — background checks for guns purchased online or at gun shows, red-flag laws designed to keep guns away from those who could harm themselves or others, and programs to bolster security at schools and other buildings.

Sen. Chris Murphy, D-Conn., who is leading the negotiations was also at the rally and said, “We are the only country in the world in which our kids go to school wondering whether they will survive the day.”

Murphy has been working to push gun legislation since the 2012 attack at Sandy Hook Elementary School in Newtown, Connecticut, that killed 20 children and six educators. He was joined Thursday by Sen. Susan Collins, R-Maine, Sen. Joe Manchin, D-W.Va., Sen. Pat Toomey, R-Pa., and others. Collins, a veteran of bipartisan talks, called the meeting “constructive.”

Although Congress hasn’t passed a meaningful gun control law since the Newtown attack, Erica Lafferty, the daughter of Dawn Lafferty Hochsprung, the slain principal of Sandy Hook, came to rally but said her first thought was to step back and not deal with it publicly.

A program manager at Everytown for Gun Safety and an advocate for universal background checks, she said: “We deserve to learn and to live without fear of being shot to death.”

Adding, “I hate that I have to be here today because it means that others have been stolen from their families. Their lives have been taken by this incredibly preventable public health crisis.”