(This article was updated to include new video content.)

During a U.S. House of Representatives hearing on Thursday, the acting director of the Secret Service revealed that he revamped the agency’s security protocols after a gunman attacked President-elect Donald Trump in July. However, his testimony did not impress everyone present.

Acting Director Ronald Rowe spoke before a House task force with seven Republicans and six Democrats that has been examining two unsuccessful assassination attempts on Trump during this year’s election race. The atmosphere became tense at certain points.

While many Republican lawmakers commended Rowe for his willingness to assist with the investigation, he clashed with Representative Pat Fallon, R-Texas, after Fallon criticized Rowe’s presence at a ceremony honoring the 9/11 attacks this year.

Fallon argued that Rowe’s appearance endangered lives by allowing him to stand behind Vice President Kamala Harris for show, insisting that Rowe compromised the safety of agents in doing so.

“Do you understand why you were there? It was for visibility, because you’re trying to impress for a role that won’t be yours,” Fallon asserted.

“Do not use 9/11 for political gain!” Rowe shouted, mentioning that he was on the ground at the World Trade Center site after the attacks and attended the ceremony to represent the Secret Service. “You crossed the line, congressman,” as both men exchanged heated remarks.

Fallon insisted he was posing “serious inquiries” about Rowe’s role in ensuring the safety of prominent officials during the event.

Rowe was appointed as acting director of the beleaguered agency in late July, following the resignation of the previous director, which came after intense scrutiny from lawmakers on both sides looking into the shooting incident. At that time, Rowe was serving as the deputy director under former chief Kimberly Cheatle.

This week’s session marked the final meeting of the bipartisan task force investigating security deficiencies that led to the assassination attempt in Butler, Pennsylvania, where Trump and two others were injured, and one man lost his life. The task force is set to release its concluding report on the event by December 13, as stipulated in the resolution creating it.