When a man with a rifle opened fire on a GOP congressional baseball practice on Wednesday morning, a few officers with the Capitol Police were present and at least one returned fire.

Sen. Rand Paul told MSNBC after the attack that the officers were the security detail for GOP Majority Whip Steve Scalise, adding that his presence at the practice therefore most likely prevented the incident from becoming a massacre.

Scalise was shot in the incident, along with multiple congressional staffers. Two Capitol Police officers were also reportedly shot.

"In the field I see Rep. Scalise is shot but moving, and he's trying to drag himself through the dirt out to the outfield," said Paul, who described a harrowing scene with congressional members and staffers running for cover as 50 to 60 shots ran out.

Paul said Scalise's leadership role in the House was what warranted the security detail he credited with neutralizing the shooter. The police on Wednesday morning said a suspect was in custody and no longer a threat.

"Everybody would've died except for the fact that Capitol Hill police were there," Paul said. "Had they not been there, it would have been a massacre."

"When you have no way to defend yourself ... the field was essentially a killing field," Paul later told CNN.

Paul spoke with MSNBC from the baseball field, where the congressional members had been ordered to shelter in place. Law-enforcement officials told CNN the attack was a deliberate attack on elected officials.