ALEXANDRIA, Va. — A lone gunman who was said to be distraught over President Trump’s election opened fire on members of the Republican congressional baseball team at a practice field in this Washington suburb on Wednesday, using a rifle to shower the field with bullets that struck four people, including Steve Scalise, the majority whip of the House of Representatives.
Mr. Trump, in a televised statement from the White House, condemned the “very, very brutal assault” and said the gunman had died after a shootout with the police. Law enforcement authorities identified him as James T. Hodgkinson, 66, from Belleville, Ill., a suburb of St. Louis.
Two members of Mr. Scalise’s Capitol Police security detail were wounded as they exchanged fire with the gunman in what lawmakers described as several chaotic, terror-filled minutes that turned the baseball practice into an early-morning nightmare. One was wounded by gunfire, and one suffered other, minor injuries.
The tragedy united Republicans and Democrats in shock and anguish. “For all the noise and all the fury, we are one family,” Speaker Paul D. Ryan said Wednesday afternoon.
Standing at second base, Mr. Scalise was struck once in the left hip, according to witnesses, and collapsed as the shots rang out, one after another, from behind a chain-link fence near the third-base dugout. Witnesses said Mr. Scalise, of Louisiana, “army crawled” from the infield to the grass as the shooting continued.
His injuries are extensive, and he was in critical condition Wednesday night, MedStar Washington Hospital Center said in a statement. As the bullet traveled across his body, it broke bones, tore up internal organs and caused major internal bleeding.
Doctors operated immediately, but additional surgery is required, the hospital said.
Mr. Trump and his wife, Melania, made a trip to the hospital on Wednesday night, arriving with two large bouquets of white flowers. The president sat privately with Mr. Scalise, and spoke with his doctors and wife, Jennifer, for about 15 minutes. He also briefly chatted with Capitol Police officers there before returning to the White House.
“Just left hospital,” Mr. Trump tweeted. “Rep. Steve Scalise, one of the truly great people, is in very tough shape – but he is a real fighter. Pray for Steve!”
Local officers arrived at the Alexandria ball field minutes after they received desperate calls for help, including calls from those still under siege at the field, the authorities said. The F.B.I. said it would take the lead in the investigation, treating it as an assault on a federal officer.
Tim Slater, special agent in charge of the bureau’s Washington field office, said that investigators were “exploring all angles” but that he could not comment on a motive. Asked whether the shooting was an assassination attempt, he said it was “too early in the investigation to say one way or another.”
The F.B.I. said Mr. Hodgkinson had a handgun and a rifle, which he bought in March, according to a law enforcement official. Witnesses described a man with white hair and a beard wielding a long gun as he stood behind the dugout.
“He was hunting us at that point,” said Representative Mike Bishop, Republican of Michigan, who was standing at home plate when the shooting began.
Mr. Bishop said the gunman had seemed to be firing a series of two shots at a time, a firearms technique known as “double-tapping,” sending off bullets that kicked up the gravel on the baseball field as they struck the ground. “There was so much gunfire, you couldn’t get up and run,” Mr. Bishop said. “Pop, pop, pop, pop — it’s a sound I’ll never forget.”
Senator Rand Paul of Kentucky, who was among the lawmakers practicing for the annual charity baseball game, which is still scheduled to take place on Thursday, told CNN that “the field was basically a killing field — it’s really sick and very sad.”
Representative Jeff Duncan of South Carolina, who left the practice just before the shooting, said afterward that he had encountered a man in the parking lot — later identified as the gunman — who “asked me if the team practicing was a Democrat or a Republican team.”
“I told him they were Republicans,” the lawmaker recalled. “He said, ‘O.K., thanks,’ turned around.”
The shooting stunned the capital as it began its workday. Out of caution, Capitol Police officials said they quickly put in place a “robust police presence throughout the Capitol complex,” and the Secret Service added security around the White House.
Mr. Ryan addressed his colleagues in the House chamber shortly after noon. “We do not shed our humanity when we enter this chamber,” Mr. Ryan said, his voice seeming to nearly break at times.
As the magnitude of the episode became apparent, House leaders canceled the day’s votes, and Mr. Trump and Vice President Mike Pence canceled speeches.
“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,” Mr. Trump said at the White House shortly after the shooting.
Mr. Hodgkinson seemed to be a fervent opponent of Mr. Trump. He signed an online petition calling for the president to be impeached, posting it on Facebook with a chilling comment: “It’s time to destroy Trump & co.”
His brother, Michael Hodgkinson, said Mr. Hodgkinson traveled in recent weeks to Washington to protest. “I know he wasn’t happy with the way things were going, the election results and stuff,” Mr. Hodgkinson said in an interview shortly after he received the news on Wednesday. He said that he had not been close to his brother and that he had not been aware of why he remained in Washington.
The F.B.I. said it appeared that Mr. Hodgkinson arrived in the area in March and had been living out of a white van near the field.
Mr. Hodgkinson also appeared to have been a fervent fan of Senator Bernie Sanders, according to a Facebook page with references to the Vermont senator. A LinkedIn page for James Hodgkinson had a profile photo showing Mr. Sanders’s famous hair and glasses and the words, “The Dawn of a New Democracy.”
In a statement Wednesday morning, Mr. Sanders said he had been told the suspect had volunteered for his presidential campaign. He offered his “hopes and prayers” for the shooting victims.
“I am sickened by this despicable act,” Mr. Sanders said. “Let me be as clear as I can be. Violence of any kind is unacceptable in our society, and I condemn this action in the strongest possible terms. Real change can only come about through nonviolent action.”
Others who were wounded included Zachary Barth, a member of Representative Roger Williams’s staff, who was struck in the leg by a bullet, and Matt Mika, a former congressional staff member and the director of government relations for the Washington office of Tyson Foods, who was shot twice in the chest.
He was in serious condition. Mr. Barth was treated at a hospital and later released.
Two of those who suffered injuries were Capitol Police officers assigned to protect Mr. Scalise, the third-ranking member of the House Republican leadership team. Officials identified the two officers as Crystal Griner and David Bailey, both 32. Officials said Ms. Griner was shot in the ankle, while Mr. Bailey suffered other minor injuries and was treated and released.
Mr. Williams, of Texas, praised the two officers as “heroes,” saying that their split-second decision to confront the gunman saved many lives.
“We saw two people risk their lives to save others; we saw courage in the face of death,” Mr. Williams said in a news conference Wednesday evening. “There could have easily been 25 deaths or more today.”
Members of the baseball team began arriving early Wednesday morning at Eugene Simpson Stadium Park, which is nestled among a neighborhood dog park, the local Y.M.C.A., a coffee shop and a grocery store.
It was the last practice before the big game on Thursday — a friendly, partisan competition that has been played to raise money for charity during most years since 1909.
By 7:09 a.m., when the first shots rang out, several dozen lawmakers, members of their staffs and a handful of others — many wearing red shirts with “Republicans” on the front — had been practicing hitting, pitching and catching for more than a half-hour.
Then bedlam erupted.
With the sound of loud bangs, one after another, people dived for cover, crouching down by the concrete wall of the dugout. Marty Lavor, an Alexandria-based photographer and former House staff member, fell on top of a lawmaker as someone shouted: “Stay down, stay down. Get closer to the wall!”
Mr. Lavor later found a bullet hole in his car.
Standing along the first-base sideline, Senator Jeff Flake of Arizona crouched near the ground and then helped Representative Mo Brooks of Alabama treat Mr. Barth, the congressional aide, who had been shot in the leg while in center field and had managed to stumble into the dugout. Mr. Brooks said he had used his belt as a tourniquet to help stop the bleeding.
“It seemed like it went forever,” said Mr. Williams, who injured his foot as he jumped into the dugout.
Standing near second base, Mr. Scalise had nowhere to hide.
Several lawmakers said they saw him go down and then try to pull himself toward the dugout with his hands. Failing to get very far, Mr. Scalise remained in the field while the barrage of bullets continued, according to several lawmakers who said they had been forced to wait until the shooting stopped to reach him.
“If not for the detail who stepped up with basic revolvers, we would’ve all been dead,” Representative Bishop said.
At a second news conference on Wednesday, Mr. Slater, the F.B.I. official, said the gunman was shot multiple times in the torso. It is not clear whether Mr. Hodgkinson was shot by Capitol Police officers or those from the Alexandria Police Department.
“It was a combat situation,” said Michael L. Brown, the Alexandria police chief.
When the hail of bullets stopped, Mr. Flake and Mr. Brooks made their way to Mr. Scalise, bringing water for him to drink. Mr. Flake told CNN that he had put pressure on Mr. Scalise’s gunshot wound. He said Mr. Scalise never lost consciousness.
The gunshots shattered the quiet morning in the residential neighborhood.
David Miller, 50, was finishing his coffee when he heard the “pop, pop.” He thought it was from nearby construction until he opened the door of the building and saw people looking for shelter and heard gunfire. “I started hollering for them to come into the building,” he said.
Five or six people came inside, at least two people in baseball uniforms and one with a baseball bat. “They were disheveled,” Mr. Miller said, “emotionally shaken, covered in dirt.”