The acting director of the Secret Service Director told a House panel investigating the assassination attempt against President-elect Donald Trump said the agency has already made changes to ensure the assassination attempt doesn't happen again amid a heightened threat environment.

"We are operating in a heightened threat environment with expanding protection requirements, and this requires a shift in the Secret Service's levels of protection, readiness and sustainability," acting Director Ronald Rowe told Congress. "A paradigm shift focuses on elevating protection, prioritizing training, strengthening our workforce and increasing accountability."

Rowe said he is creating the Office of Field Operations "to reset our thinking, thinking and perspective about the role field offices play in protection and to enhance our operational effectiveness by better leveraging field offices to support, enable and inform protection and protective activities."

"The world is a dangerous place. Responsibilities of the Secret Service are critical to the national security of the United States, it is important that decision makers fully recognize and appreciate the vital role and significance of the Secret Service in our nation's security,” he said.

The hearing was disrupted when Rowe got into a screaming match with Republican Rep. Pat Fallon of Texas over Rowe's attendance at the 9/11 memorial. Fallon accused Rowe of putting the president's Secret Service detail out of position so he could sit behind him during the ceremony.

Before the exchange, Rowe said that the agency will use GPS blue force trackers -- a military asset that uses GPS to show where friendly and hostile assets are.

He also asked Congress for more money to make sure the agency will have the preventive resources it needs and that it has already put the supplemental money to good use.

"We've also started moving money out to acquire more materials that we needed as we started to put more assets out on the road, classified assets, ballistic assets, now the wear and tear on that is going to increase," Rowe said. "So now we have to make sure that we can acquire more and put more money down on contracts so that, as we are going to now go through the service life of these materials, we have to be able to replenish them and replenish them quickly. So some of these are long, lean items, so that money has been very, very helpful to us in making sure that we can address our immediate needs."

He said the agency has about 500 agents in "various statutes of training between now and March."

The agency "is on pace" to hire 650 special agents and 350 uniformed division agents.

Rowe said he is standing up an "auditing capacity" to regularly send feedback to agents to ensure they are doing the best job possible.

"We're not here to take punitive action against people, just to, you know, just to get you for something," he said. "No, we want to make the mission better."

Rowe also said that he stood up a drone unit that is actively hiring, and that if there had been a counter-drone mechanism on the ground in Butler, the attempt might have been stopped.

"My goal is to get more drone operators and people with this expertise downrange in the field, so that they can go out and do this and are there on the ground, and that's going to help us fly drones and identify line of sight vulnerabilities, get that ‘eye in the sky’ perspective as we're doing our advance," he said.

He also said he made changes like getting state and local partners on the same radio frequencies.