Sen. Chris Murphy (D-Conn.) is introducing legislation to expand background checks for gun purchases in the wake of a mass shooting in Las Vegas that killed at least 59 people and left more than 520 wounded or injured. 

“I’ll be introducing a new background checks bill shortly,” Murphy told reporters on Monday.

He added that he was still discussing the forthcoming legislation with other members of the Democratic caucus. 

{mosads}The Las Vegas violence at a country music festival has become the deadliest mass shooting in modern U.S. history, breaking a record set just over a year ago at the Pulse nightclub in Orlando, Fla.

Murphy has become a prominent critic of the nation’s lack of gun control, his voice rising with each  mass shooting across the country.  

Murphy acknowledged that it’s not yet clear if stronger background checks would have prevented Sunday’s shooting, but argued that it could have saved dozens of others who are shot, on average, each day in the United States. 

“The fact is 80 other people died from guns yesterday and stronger background checks laws would have saved many of them,” he said. 

Murphy noted he was still working out the timing of when he would introduce the legislation. 

A group of Democratic senators, including Murphy, introduced legislation in 2016 that would have required a background check for nearly every sale or transfer of a gun. 

But senators rejected both that measure, and a GOP alternative, last year, just days after the shootings at Pulse. 

Given those votes, any background check or gun control bill faces an unlikely path forward in a GOP-controlled Congress.