Omar Gonzalez, 42, who broke into the White House on Friday, was viewed as a threat to the president, new evidence suggests.

The former sniper who broke into the White House on Friday was twice found with a cache of weapons and was viewed as a threat to the president, according to damning new evidence that has prompted an urgent review of security surrounding Barack Obama.

After Omar Gonzalez, a 42-year-old Iraq war veteran, scaled the perimeter fence, sprinted across the north lawn and carried a knife into the residence, prosecutors revealed on Monday that a search of his nearby car uncovered 800 rounds of ammunition, a machete and two hatchets.

It also emerged that Virginia police searched Gonzalez’s car after a high-speed chase in July and found an illegal sawn-off shotgun, two powerful rifles, four handguns and a map of Washington with a line drawn pointing to the White House.

Although President Obama had left minutes before the incident on Friday, growing information on the threat posed by Gonzalez has led to criticism of White House procedures, particularly after officials appeared to acknowledge that the front door of the residence was unlocked.

The incident, which only ended after Gonzalez was tackled by an officer inside the main north portico entrance to the White House residence, has also raised a host of more lasting questions, including whether the secret service is doing enough to protect a president who reportedly faces more death threats than any other.

White House spokesman Josh Earnest said it was important to strike a balance between security and continued public access, pointing out that the door is used by thousands of official visitors to the White House, and would be locked in future.

“The secret service has the challenging task of balancing the need to ensure the safety and security of the first family, while also ensuring that the White House continues to be the people’s house,” he told reporters.

There have been several dozen incidents of people jumping the fence in recent years, including a toddler who slipped through the railings only last month, but it is highly unusual for someone to gain entrance to the residence itself and Earnest confirmed that part of the security review would look at why Gonzalez was not stopped by the dog patrols, snipers and other offices who guard the site.

“There’s already some stepped up training for officers who are essentially standing on the front lines of the White House to ensure that they are aware of the policies and procedures that are related to securing the White House and dealing with incidents like the one that we saw on Friday,” he said.

The culture and effectiveness of the US secret service has been under growing scrutiny in recent months, especially after an agent was found drunk in the hallway of a Dutch hotel during a presidential visit in March, and after several agents were accused of buying prostitutes during a summit in Colombia 2012.

Though there were higher than usual numbers of guards in evidence on Monday, the mood in one guard hose used to access the site by journalists was not visibly different from normal, and some guards could be seen chatting and laughing among themselves.

Police in Washington have also been accused of over-reacting to intruders in the past, most recently when a woman who attempted to drive her car into a White House gate with a young baby inside was shot and killed.

Politicians including Washington DC delegate Eleanor Holmes Norton have also criticised one option in the security review which would see the area in front of the White House permanently closed to members of the public.

“Another challenge the secret service deals with … there are overlapping jurisdictions in place, that the secret service does have to work very closely with Park Police and with the Metropolitan police department, as they provide security here at the White House,” Earnest said.

Obama, who had taken off by helicopter bound for Camp David just minutes before the incident, was briefed “multiple times”.

“His family lives in the White House, and so he is obviously concerned by the incident,” added Earnest.

In another option under review according to officials, US secret service agents are considering a plan to cordon off a public plaza that fronts the property, and install security checkpoints a few blocks away, according to a New York Times report.

 

Visitors bags may be searched at the checkpoints, but the security gates would be unlikely to include body scanners or metal detectors, such as those used by the Transportation Security Administration.

The White House Historical Association, one of several agencies that would be affected by changes to security protocols, said it is supportive of the secret service’s “exploratory process”.

“We’re taking a wait-and-see approach,” said historical association spokesperson Lara Kline. “At this time we are in collaboration waiting and listening to hear from the secret service how they would like to move forward.” An internal investigation is also being conducted.

In addition to the historical association, security changes would likely require input from the Metropolitan police and US Parks police. Currently, at least eight separate agencies are participating in the security review process, the historical association said.

Republicans have been critical of the secret service since Gonzalez, of Copperas Cove, Texas, was able to scale a black iron fence surrounding the property around 7.20pm Friday, armed with a three-and-a-half inch knife, and enter the White House’s front door. Another man was arrested Saturday, after he drove up to the White House gate in his car and refused to leave.

“Unfortunately, they are failing to do their job,” said Jason Chaffetz, chairman of the House oversight and government reform subcommittee. “These are good men and women, but the secret service leadership has a lot of questions to answer. Was the door open?”

The open public plaza itself is the result of a perceived need for greater security. Pennsylvania Avenue, the road running in front of the White House, was open to vehicle traffic until a the a car bomb destroyed part of the Alfred P Murrah federal building in Oklahoma City in April 1995. The same year, a man used a semi-automatic weapon to spray bullets at the facade of the building.

In the fall of 1994, a small plane crashed into the property’s lawn.