President Joe Biden tweeted Monday, "Once again, our nation mourns after a senseless act of gun violence."

“Jill and I pray for the lives lost and impacted by today's shooting. Too many Americans are paying for the price of inaction with their lives," he wrote. "When will Republicans in Congress act to protect our communities?”

White House press secretary Karine Jean-Pierre said at Monday's briefing, "Once again, today the president has called on Republicans in Congress to work together with Democrats to take action to ban assault weapons and high-capacity magazines, to require safe storage of firearms, to require background checks for all gun sales, to eliminate gun manufacturers' immunity from liability."

"These are common sense actions we can ask for and should be getting right now," she said.

"We need to act and we need Republicans to show some courage," she said.

Two officers and seven civilians were injured in the Louisville shooting, according to the University of Louisville Hospital.

One of those officers is in critical condition, according to police.

At least three patients have already been discharged, according to the hospital.

Republican leader and Kentucky Sen. Mitch McConnell, who lives in Louisville, tweeted that he's "devastated" by the news of Monday morning's mass shooting.

"We send our prayers to the victims, their families, and the city of Louisville as we await more information," McConnell tweeted.

His fellow Kentucky senator, Rand Paul, tweeted, "Our hearts break for the families of those lost."

President Joe Biden has been briefed on the shooting, a White House official confirmed to ABC News.

-ABC News' Allie Pecorin and Justin Gomez

Officers arrived at the Old National Bank within three minutes of being dispatched and found the suspect still firing, Louisville police said.

Officers exchanged gunfire with the suspect who died at the scene, police said. It's not yet clear if the suspect's wounds were self-inflicted, police said.

Four victims were killed and eight people are injured, police said.

At least two officers were shot during the exchange of gunfire, police said, including one who is undergoing surgery.

It appears the suspect was a previous or current employee, police said.

"This is awful. I have a very close friend that didn't make it today. And I have another close friend who didn't, either, and one who is at the hospital that I hope is gonna make it through," Kentucky Gov. Andy Beshear said at a news conference.

"The safety of Old National Bank employees and everyone we serve in our banking center locations is paramount,” Jim Ryan, the CEO of Old National Bank, said in a statement. “As we await more details, we are deploying employee assistance support and keeping everyone affected by this tragedy in our thoughts and prayers."

Louisville police have released the dramatic 911 calls from Monday's mass shooting inside a bank.

One woman who called 911 said about eight or nine people have been shot. She said she was hiding in a closet in the first-floor conference room.

She told the dispatcher she knew the shooter, who worked with her.

Loud gunshots are heard booming in the background as the employee recounted what was happening.

The dispatcher told the woman to stay quiet and stay where she was. Whispering, she told the dispatcher there was a lot of blood.

The mother of the suspected gunman, 25-year-old Connor Sturgeon, called 911 to say her son's roommate called her and was concerned.

"He apparently left a note," she said.

"He's never hurt anyone, he's a really good kid," Sturgeon's mother told the dispatcher. "I don't know where he would've gotten a gun."

"I know he doesn't own any guns!" she told the dispatcher.

Sturgeon, who was killed by police at the scene, bought the AR-15 used in the attack legally on April 4 in Louisville, according to police.