A top Republican lawmaker and several congressional aides were injured when a gunman sprayed bullets on them as they practised for an annual baseball game in a Washington suburb in what reports said appeared to be a "deliberate attack".
House Majority Whip Steve Scalise, 51, was shot in the hip during the practice at a field in Alexandria, Virginia by the yet-to-be-identified rifle-wielding man, who was shot dead by the police.
Scalise's aides said the congressman was stable.
He was first elected to Congress in 2008, after serving as a member of the Louisiana state legislature for more than a decade. Scalise served as majority whip for roughly three years.
A second congressman Roger Williams was also injured, but it was unclear if he was shot or injured in some other way.
"Five people were transported medically from the scene," Alexandria police chief Michael Brown told reporters.
The gunman was shot at by the police, apprehended and taken to a hospital. Later US President Donald Trump in a televised address from the White House announced the shooter has died.
He also praised the Capitol Police. "Many lives would have been lost, if not for the heroic actions of the two Capitol police officers who took down the gunman despite sustaining gunshot wounds during a very, very brutal assault."
According to a senator, nearly 50 shots rang out during the exchange of fire between the gunman and the lawmakers' security detail. He said the suspect was a white man with dark hair, apparently in his 40s or 50s, and was wearing jeans and a blue shirt.
About 25 senators and congressmen were practicing for more-than-a-century-old Congressional Baseball Game scheduled for June 15 at Nationals Park when the shooting took place.
The CNN quoting congressional and law enforcement sources said the shooting appears to be a "deliberate attack" and lasted for about 10 minutes.
Congressman Ron DeSantis, who left the scene just before the shooting began, said a man had asked him if it was Republicans or Democrats practicing as he walked to his car. "About three minutes later, at around 7:15 am the shooting began."
The Federal Bureau of Investigation (FBI) said it would take the lead over the shooting investigations.
The shooting targeting Congressmen has shocked many in the US, where an intense debate is raging on gun control.
Earlier today, Trump in a statement said he was closely monitoring the developments in Virginia. "The vice president (Mike Pence) and I are aware of the shooting incident in Virginia and are monitoring developments closely," Trump said.
"We are deeply saddened by this tragedy. Our thoughts and prayers are with the members of Congress, their staffs, Capitol Police, first responders, and all others affected," the president said.
According to a White House official, Trump has spoken to Scalise's wife, the Speaker of the House, and other leaders of the Senate.
Senator Rand Paul described the scene as "sort of a killing field". "Without the Capitol Hill police it would have been a massacre," he told Fox News.
Congresswoman Nancy Pelosi called the shooting a "despicable and cowardly attack." "We are profoundly grateful for the heroism of the Capitol Police, whose bravery under fire undoubtedly saved countless lives. On days like today, there are no Democrats or Republicans, only Americans united in our hopes and prayers for the wounded," she said.
Senator Dick Durbin said, "We owe an enormous debt of gratitude to the United States Capitol Police who put their lives on the line this morning and each and every day to keep members, staff, and visitors safe."
Indian-American Congressman Raja Krishnamoorthi called it a horrible, senseless violence.
"I was not at the scene today, but my thoughts and prayers are with Congressman Scalise, the Capitol Police officers and others who were shot, and their families," he said.