The man who opened fire on politicians and police officers in the USA has died from his injuries, Donald Trump has said.
A government official identified the suspect as James Hodgkinson, a 66-year-old man from Illinois.
In a statement, Mr Sanders said he was ‘sickened by this despicable act’.
Top Republican politician Steve Scalise was shot and injured when the gunman targeted the group at a baseball field in Virginia.
Hodgkinson has had several minor run-ins with the law in recent years and belonged to a Facebook group called ‘Terminate the Republican Party’.
Until recently, he ran a home-inspection business from his home in Belleville, Illinois, according to his Facebook page
Speaking from the White House, Mr Trump also praised the actions of two officers who ‘took down’ the gunman during a shootout.
The president also called for unity, telling Americans strength comes from when ‘we work together for the common good’.
He said: ‘The assailant has now died from his injuries.
‘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.
‘We may have our differences but we do well in times like these in times like these 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 that our children deserve to grow up in a nation of safety and peace and that we are strongest when we are unified.’
Republican Jeff Duncan believes he spoke with the suspect, who asked whether it was Republicans or Democrats playing.
Mr Duncan, of South Carolina, said a man matching the description of Hodgkinson approached him and asked: ‘Excuse me, sir, who’s practicing today? Democrats or Republicans?”
Mr Duncan replied it was the Republican team, and the man thanked him and turned around.
Nothing about the man ‘struck me as being out of the ordinary’, Mr Duncan added.
Four people were injured during a congressional batting practice just outside Washington DC, including Mr Scalise, the House of Representatives majority whip.
The 51-year-old is in a stable condition at George Washington University Hospital, and his injuries are not thought to be life-threatening.
Senator Jeff Flake, of Arizona, said: ‘We were doing batting practice.
‘All of a sudden we heard a very loud shot. The gunman was over by the third base dugout with a clear view of the field.’