WASHINGTON (NEXSTAR) — The mayor of Highland Park, Illinois, where a gunman opened fire at a Fourth of July parade, testified before Congress Wednesday to call for a ban on assault weapons.

Nancy Rotering said she will “be haunted forever” by the shooting that killed seven people and injured dozens more.

“We were screaming, ‘Run! Shooter!'” she recalled. “Less than a minute is all it took for a person with an assault weapon to shoot 83 rounds into a crowd, forever changing so many lives.”

She and Sen. Tammy Duckworth, D-Ill, said a ban on assault-style weapons could help prevent future shootings. Duckworth, a veteran of the Iraq War, said assault weapons belong only on the battlefield.

“We don’t have to live this way,” Duckworth said. “We can still hunt, we can still have an armed citizenry. We can do all of that … without weapons of war.”

Republicans argue a ban would not stop killings and would instead only stop law-abiding citizens from protecting themselves “against the horrible spike in violent crime that began two years ago,” Sen. Chuck Grassley, R-Iowa, said.

He and fellow Republicans say Democrats ought to focus their attention on improving mental health.

“We can’t keep seeing shooter after shooter follow the same predictable path and nobody does anything about it,” Grassley said.

Congress recently passed gun safety legislation putting millions toward that effort, but Sen. Dick Durbin, D-Ill., said he will also keep pushing for the assault weapons ban. House Democrats are planning to vote on such a ban, but it’s unclear when or if the Senate may do the same.

“I voted for the first assault weapons ban. I’ll do it again,” Durbin said. “America must do better.”