Major lapses in the U.S. Secret Service's operations allowed an armed intruder inside the White House in late September, according to the findings of an investigation by the Department of Homeland Security, which were revealed Thursday night. The summary of the report blamed lack of training, communication failures and staffing shortages.

The report found that a Secret Service agent with an attack dog did not respond on time when the intruder, identified as Omar Gonzalez, jumped the fence of one of the most securely guarded buildings in the world, armed with a pocket knife, on Sept. 19. The officer was on a personal call at the time and was without his radio earpiece, leading him to miss a radio traffic alert about the fence jumper, and only responded after he saw another uniformed officer running toward the White House, the report revealed.

"A combination of technical missteps, lack of radio discipline, improper use of equipment and aging infrastructure contributed to communications failure on the date of the incident that delayed notification to key Officers,” the report said.

The report also provided details of the incident from the time Gonzalez began his attempt to jump the White House fence.

“Several Uniformed Division personnel were stationed at the Northwest gate on Pennsylvania Avenue, but none of them saw Gonzalez as their views were obstructed by a construction project along the fence line,” the report said. It added that an officer posted outside the North Portico doors also failed to see the intruder as the “view was obstructed by bushes, pillars and the vehicles parked in front of the Portico.

“After attempting twice to physically take Gonzalez down but failing to do so because of the size disparity between the two, the officer then attempted to draw her baton but accidentally grabbed her flashlight instead,” the report said. “The officer threw down her flashlight, drew her firearm, and continued to give Gonzalez commands that he ignored.”

The Emergency Response team members “were unfamiliar with the layout of the White House, and waited to assemble into a tactical formation before entering the North Portico door,” the report said. “By the time they entered Gonzalez had already been subdued. Gonzalez was subsequently handcuffed, searched, and escorted out of the White House.”

The report also stated that the alarm and radio systems were not functioning properly, and that the doors to the White House, which were believed to be closed, were open.

Several factors including “the Emergency Response Team’s reliance on the canine unit and erroneous belief that the bushes were an impassable barrier; the effect of inadequate information, poor visibility, and other factors; the tactical response of USSS Officers at the scene; and lack of an automated locking mechanism for the White House doors,” were also responsible for the incident, the report said in the summary.

The September incident, coming after a series of missteps from the Secret Service, which is charged with the president's security, triggered severe criticism of the agency and also resulted in the resignation of U.S. Secret Service Director Julia Pierson.