Former U.S. Capitol Police Chief Steven Sund said during a congressional hearing Tuesday that he regrets resigning in the days after the Jan. 6 insurrection, as he argued intelligence failures were to blame in allowing a "coordinated attack" that overwhelmed officers at the Capitol and saw rioters storm the building he was sworn to protect.

As the Senate Homeland Security and Governmental Affairs (HSCAC) and Rules and Administration committees convened seeking information on the preparation and response to the attack, Sen. Ron Johnson, R-Wisc., asked Sund, "Do you regret resigning?"

"Yes, I do sir," Sund responded. "I certainly do regret resigning. I love this agency. I love the women and men of this agency and I regret the day I left."

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During a separate line of questioning by Sen. Roy Blunt, R-Mo., Sund and House Sergeant-at-Arms Paul Irving also could not agree on when National Guard assistance was requested.

Sund said he submitted the request at 1:09 p.m. on Jan. 6. But Irving insisted he did not receive the request for National Guard support until after 2 p.m. while in former Senate Sergeant-at-Arms Michael Stenger’s office. When pressed, Irving said he took a call from Sund before while on the Congress floor.

Former U.S. Capitol Police Chief Steven Sund testifies before a Senate Homeland Security and Governmental Affairs & Senate Rules and Administration joint hearing on Capitol Hill, Washington, Tuesday, Feb. 23, 2021, to examine the Jan. 6 attack on the Capitol. (Erin Scott/The New York Times via AP, Pool)

Former U.S. Capitol Police Chief Steven Sund testifies before a Senate Homeland Security and Governmental Affairs & Senate Rules and Administration joint hearing on Capitol Hill, Washington, Tuesday, Feb. 23, 2021, to examine the Jan. 6 attack on the Capitol. (Erin Scott/The New York Times via AP, Pool)

All three men resigned in the days after the insurrection. Sund and Irving did not concur on the timeline regarding the National Guard request before Blunt ran out of time for his questioning. Sen. Johnson, who was tapped next, suggested that phone records be dug up in the future.

Earlier during his opening statement, Sund said the insurrection on Jan. 6 was a "clear lack of intelligence information," and was "not poor planning" by the U.S. Capitol Police. He explained that the force relies on cooperation between difference intelligence and law enforcement agencies.

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Intelligence available before Jan. 6 suggested that the events would be similar to a previous Million MAGA event in December, which involved White supremacist groups, including the Proud Boys, and other extremist groups like Antifa and that those participating could become violent, Sund said.

"We had planned for possibility of violence and possibility of people being armed but not possibility of coordinated attacks," Sund told members of Congress, explaining that rioters were equipped with their own radio system, planted pipe bombs, and had brought climbing gear and explosives to the Capitol.

 "These criminals came prepared for war," Sund said.

Former U.S. Capitol Police Chief Steven Sund Sund said the insurrection on Jan. 6 was a "clear lack of intelligence information," and was "not poor planning."  (AP Photo/Andrew Harnik, Pool)

Former U.S. Capitol Police Chief Steven Sund Sund said the insurrection on Jan. 6 was a "clear lack of intelligence information," and was "not poor planning."  (AP Photo/Andrew Harnik, Pool)

Sund, Irving and Stenger also testified that they had not seen the FBI report of raw data that was released on eve on Jan. 5 that provided information on Jan. 6 event. Irving said a call between him, Stenger and Sund the night before suggested "intelligence didn’t warrant" National Guard.

"The events of January 6th went beyond disobedience," Stenger also said during his own remarks. "This was a violent, coordinated attack where the loss of life could have been much worse."

Throughout the hearing, Metropolitan Police Chief Robert Contee testified that he was "stunned" by the Army’s response as Sund was pleading for National Guard response during the afternoon of Jan. 6. As calls from the Capitol grew more chaotic, Army officials said they did not deny the request but discussed concerns in deploying Guardsmen since they were not prepositioned in advance.

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Officials serving in the Pentagon at the time of the insurrection will testify next week about their response to the Capitol breach and allegations that they slow-walked National Guard approval, Sen. Amy Klobuchar, D-Minn., announced on Tuesday.

Contee said Tuesday he wants the authority to change the mission of the DC National Guard from the Pentagon to the D.C. mayor. Furthermore, Sund argued that the FBI needs to broaden the extent of information it collects on domestic extremists.

Fox News' Jennifer Griffin and Lucas Tomlinson contributed to this report.