An intruder who jumped a fence at the White House made it further inside the building than the US Secret Service has publicly acknowledged, according to reports.
The disclosures in the Washington Post and New York Times came ahead of a congressional oversight hearing with the director of the embattled agency assigned to protect president Barack Obama's life.
The newspapers said Omar J Gonzalez ran past the guard at the front door and into the East Room, which is about halfway across the first floor of the building.
Gonzalez was eventually "tackled" by a counter-assault agent during the incident on September 19, according to the Post.
In the hours after the incident, Secret Service spokesman Ed Donovan told reporters that the suspect had been apprehended just inside the North Portico doors of the White House.
The Secret Service also said that night that the suspect had been unarmed - an assertion that was revealed to be false the next day when officials acknowledged Gonzalez had a knife with him when he was apprehended.
Getting so far would have required Gonzalez to dash through the main entrance hall, turn a corner, then run through the centre hallway half-way across the first floor of the building, which spans 168ft in total, according to the White House Historical Association.
Secret Service director Julia Pierson is scheduled to testify before a House committee for the first time since the incident.
The new details about a far more significant breach were expected to dominate inquiries.
A Secret Service spokesman declined to comment on the latest details because of the continuing investigation.
No-one was hurt in the incident, but it raises the question of whether the latest breach is part of a pattern of delayed reactions to threats to the executive mansion, which the Secret Service denies.
The Post reported over the weekend that the Secret Service did not immediately respond to shots fired at the White House in 2011, amid what the agency describes as uncertainty about where the shots originated. Four days later, it was discovered that at least one of the shots broke the glass of a window on the third level of the mansion, the Secret Service said.
At the time of the 2011 breach, the president and first lady Michelle Obama were away, but their daughters were in Washington - one at home, and the other due to return that night.
Oscar R Ortega-Hernandez of Idaho has been sentenced to 25 years in prison for the 2011 incident.
Gonzalez, 42, was arrested after agents stopped him inside the White House front door.
White House spokesman Josh Earnest said: "The president and the first lady, like all parents, are concerned about the safety of their children, but the president and first lady also have confidence in the men and women of the Secret Service to do a very important job, which is to protect the first family."
Ms Pierson has ordered a review of the incident and possible changes to security measures at and around the White House. She briefed the president over the incident on Thursday.