Monday’s deadly school shooting in Nashville, Tenn., is leading to renewed calls from Democratic lawmakers for tougher gun laws – and renewed pushback from Republicans.

A shooter armed with two AR-15-style rifles fatally wounded six people – three 9-year-old students and three adults – Monday at The Covenant School, a small Presbyterian school for preschool through sixth grade, police said.

Police shot and killed the shooter – 28-year-old Audrey Hale – inside the school, authorities said.

It's the latest in a long list of U.S. school shootings, which also include last year’s massacre at Robb Elementary School in Uvalde, Texas, that left 21 people, including 19 children, dead. It also follows recent mass shootings in places such as stores, nightclubs, movie theaters and houses of worship.

Metro Nashville Police Chief John Drake said Tuesday that Hale legally purchased seven firearms, including the three used in the shooting. He said investigators have still not determined a motive but said Hale was being treated for an “emotional disorder.”

Within hours of the attack, President Joe Biden repeated his call for Congress to pass a ban on semi-automatic weapons.

“We have to do more to stop gun violence,” Biden said Monday. “It's ripping our communities apart, ripping at the very soul of the nation. And we have to do more to protect our schools so they aren't turned into prisons.”

He reiterated the point Tuesday during a trip to North Carolina about the economy.

"Those children should all be with us still," Biden said. "As a nation, we owe these families more than our prayers, we owe them action ... we need to act, these are weapons of war."

Referencing the bipartisan gun safety bill Congress passed last year, Biden said: "Don't tell me we can't do more together. So I again call on Congress to pass the assault weapons ban. Pass it, it should not be a partisan issue, it's a common sense issue. We have to act now.

"People say, why do I keep saying this if it’s not happening?” Biden added. “Because I want you to know who isn’t doing it, who isn’t helping, to put pressure on them.”

During an interview on MSNBC's "Morning Joe" on Tuesday morning, White House press secretary Karine Jean-Pierre said of mass shootings: “It’s enough. Enough. Enough.”

Jean-Pierre noted that Biden has authorized more than 20 executive actions aimed at reducing gun violence and signed bipartisan legislation last year that strengthened background checks for gun buyers 21 and under, offered states incentives to implement “red flag laws” and closed a gun loophole for domestic abusers.

But Congress must act to make more meaningful changes, Jean-Pierre said.

“We need Republicans in Congress to show some courage,” she said. “This is what they owe these parents. This is what they owe these family members who are losing their loved ones. They need to show courage.

“We need gun safety laws, comprehensive gun safety laws,” Jean-Pierre continued. “We need to ban assault rifles. Those weapons of war do not belong in our streets. They do not belong in schools.”

Many congressional Democrats joined the chorus calling for tougher gun laws.

“No one should pretend like we can’t choose to end this carnage,” Sen. Chris Murphy, R-Conn., tweeted. “It’s our decision to let it continue.

“It's an utter disgrace that children in America today are going to school afraid of being shot and killed,” Sen. Bernie Sanders, I-Vt., who caucuses with Democrats, wrote on Twitter. “We can't allow this epidemic of gun violence to continue. How many more have to die before Congress acts?”

“If we truly care about our children, we must break the NRA’s grip for good & pass stronger gun safety legislation,” tweeted Sen. Sheldon Whitehouse, D-R.I.

But Republicans seemed resistant.

“I would say we’ve gone about as far as we can go — unless somebody identifies some area that we didn’t address,” Sen. John Cornyn, R-Texas, who negotiated last year’s gun bill with Murphy, told reporters Monday.

"With respect to any discussion of legislation, it's premature," said South Dakota Sen. John Thune, the No. 2 Republican in the Senate. "There's an ongoing investigation and I think we need to let the facts come out."

"It’s just premature to talk about it," Thune added when pressed on the topic.

Republican presidential candidate Nikki Haley said during a town hall in New Hampshire on Monday that more metal detectors, not more gun restrictions, are the answer.

“It's OK if there are metal detectors,” she said. “ … The kids see them in an airport. They see them wherever they go. Why don't we do that to protect those kids?

“Everybody wants to talk about gun control. My thing is, I don't want to take away your ability to protect yourself until they do those things that protect those kids,” she added.

Meanwhile, Rep. Tim Burchett, R-Tenn., declared nothing could be done.

“It's a horrible, horrible situation, and we’re not going to fix it,” he told reporters Monday. “Criminals are going to be criminals, and my daddy fought in the Second World War, fought in the Pacific, fought the Japanese, and he told me, he said, ‘Buddy … if somebody wants to take you out and doesn't mind losing their life, there's not a whole heck of a lot you can do about it.”

Democrats have been countering such arguments by saying that mass shootings are a unique problem to the U.S.

“No other country is dealing with this,” Jean-Pierre said in her MSNBC interview. “No other country is dealing with our kids going to school and being slaughtered, being murdered, teachers being slaughtered, being murdered. And we're seeing this in grocery stores. We're seeing this in churches, at places of worship.”

Murphy told CNN on Monday night he thinks Democrats “can still continue to work to find common ground” with Republicans on gun legislation.

“You shouldn't take guns away from law- abiding citizens, but you should make sure that criminals and people who are seriously mentally ill don't get their hands on guns and that we should take these military-assault weapons off the streets,” he said.

Murphy said Democrats might not have the votes to pass a ban on semi-automatic firearms, but he thinks Congress might be able to build on last year’s legislation, which was the first it passed on guns in 30 years. When asked what a new bill might look like, Murphy declined to go into specifics.

“I think it's hard for me to negotiate with my Republican colleagues on live TV,” he told CNN’s Anderson Cooper. “We will work hard to try to find” common ground.