Zack Barth, an aide to Rep. Roger Williams (R-TX), described the moment he was shot in the leg during Wednesday's attack on Republican members of Congress. 

Barth said on "Fox & Friends" he was shagging fly balls in the outfield at the baseball practice in Alexandria, Virginia, when the shooting began. 

'This Isn't a Gun Issue': Loesch Rips McAuliffe For Gun Control Rhetoric After Shooting

Rep. King on Scalise Shooting: There Are 'Psychotic People' on Both Sides

He said he saw the shooter with a long gun near the third base dugout taking "deliberate aim" at people on the field. 

Barth said the best thing he could do was get on the ground and make himself the smallest target possible as the gunman took aim at him. 

"It just starts popping all around me, he hits me in the leg. At that point, my adrenaline is pumping and my fight or flight reflexes take control. I decided if I want to live, I need to get to better cover," said Barth. 

Bleeding from his leg, he said he ran as fast as he could and jumped into the first base dugout with Rep. Williams and they took cover.

"I was just concerned about staying alive," said Barth. 

Barth posted on Facebook after the shooting that he had been wounded but was "okay."

Barth described the scene as "chaos," adding he might not have made it through without the heroic actions of the police officers on the scene.

Rep. Williams said Barth and the Capitol Hill police officers who took down the gunman are all heroes. 

"All we had was balls and bats to fight this guy," said Williams. 

Watch the riveting account above.

Gingrich: Scalise Shooting Is Part of a Pattern of 'Hostility on the Left'

Gillian Turner: Scalise Shooting Is a 'Wake-Up Call for Bipartisanship'

Scalise Shooting Suspect Identified as James Hodgkinson