Trump: Assailant who shot GOP Rep. Steve Scalise, others has died
"Had they not been there, it would have been a massacre," eyewitness Sen. Rand Paul, R-Ky., said of the Capitol Police. The officers were present because Scalise is a member of the congressional leadership.
Rep. Roger Williams, R-Texas, said a member of his staff was shot and is receiving medical attention.
President Donald Trump later said that the assailant died. He did not name the suspect.
The suspected shooter was identified by NBC News as 66-year-old James Hodgkinson of Illinois. Emergency services transported five injured people from the scene, said Michael Brown, chief of the Alexandria Police Department. Brown did not identify the injured people.
Several GOP congressmen and at least two Republican senators attended the practice, Paul told MSNBC. They were practicing for an annual, bipartisan charity baseball game set to take place on Thursday at Nationals Park. That game will go on, according to NBC News.
South Carolina Congressman Jeff Duncan told CNBC that a man asked him whether the people on the field were Democrats of Republicans. Rep. Ron Desantis, R-Fla., who was with Duncan, later told CNBC that the pair saw pictures of Hodgkinson and believe it was the same person.
It is too early to tell if the shooting was a targeted attack, said Tim Slater, a special agent in charge of the FBI's Washington field office.
Paul and Rep. Mo Brooks, R-Ala., described the weapon used by the shooter as a rifle. Paul said he heard a first, "isolated" shot followed by a "rapid succession" of 5 to 10 shots.
Rep. Jack Bergman, R-Mich., told CNBC that the first shot came "from somewhere behind the third base dugout and then the second shot came shortly thereafter." They then "knew it was something real, so people started scrambling."
"We are very fortunate. It could have been a whole lot worse," he said.
Capitol Police and Alexandria police officers who responded to the scene exchanged fire with the shooter, according to Capitol Police Chief Matthew Verderosa.
Brooks told CNN that he saw Scalise drag himself from second base into the outfield after he was shot, leaving a trail of blood 10 to 15 yards long. Sen. Jeff Flake, R-Ariz., said Scalise lay by himself for "at least 10 minutes," as people could not get to him amid the shooting.
"I wanted to get to him but there were still shots going overhead from both sides," he said.
Rep. Brad Wenstrup of Ohio, a former combat surgeon, applied pressure to the wound, Flake said. Scalise remained coherent throughout.
Wenstrup told CBS News that he "felt like [he] was back in Iraq."
Trump said the two Capitol Police officers "took down the gunman despite sustaining gunshot wounds."
Many scheduled House hearings for Wednesday got delayed or canceled. The chamber also canceled votes for the day, according to multiple reports.
After the shooting, Trump called for unity after the shooting.
"We may have our differences, but we do well in times like these to remember that everyone who serves in our nation's capital is here because, above all, they love our country. We can all agree that we are blessed to be Americans ... and that we are strongest when we are unified and when we work together for the common good," the president said.
He called Scalise a "patriot" and a "fighter."
House Speaker Paul Ryan tweeted that the "hearts of the whole House" are with Scalise and others who were at the scene.
Rep. Ruben Kihuen, D-Nev., shared a photo of Democrats at their baseball practice praying for the Republicans.
This story is developing. Please check back for further updates.
Click here for the latest on the markets.
— CNBC's Katie Little contributed to this report
Oroville Dam repair costs will top $500 millionCNBC
3 killed, 2 wounded at Maryland office park shootingCNBC
A fire department in Puerto Rico is now powered by solar: 'It's a matter of life and death'CNBC
Hundreds missing, 26 dead in California wildfires as crews gain groundCNBC
On the Fed choice, if it ain't Yellen, I'll be sellin'CNBC