White House intruder 'had ammo and a machete in his car'
The man who broke into the White House on Friday evening had 800 rounds of ammunition, a machete and two hatchets in his car, authorities have said.
Omar Gonzalez, 42, was carrying a knife when stopped by Secret Service officers just inside the building.
On Monday officials said he was also arrested in July with two rifles and a map marking the White House.
The Secret Service says it has stepped up security and launched a comprehensive review of procedures.
Mr Gonzalez, a US military veteran who was decorated for his service in the Iraq war, faces charges of unlawfully entering a restricted building carrying a "deadly or dangerous weapon".
During his court hearing on Monday, federal prosecutors also said Mr Gonzalez was stopped but not arrested in August after he walked past the White House with a hatchet.
Assistant US Attorney David Mudd said that the accused intruder was a danger to the president, and a judge agreed to hold him in jail until a hearing in October.
Video footage showed Mr Gonzalez running across a White House lawn after scaling a fence on Friday.
Mr Gonzalez was only stopped after entering the North Portico doors, the Secret Service said. He was later found to be carrying a 9cm (3.5in) folding knife.
The president and his daughters had just left the White House by helicopter before Mr Gonzalez entered, but White House press secretary Josh Earnest said Mr Obama was "obviously concerned" about what happened.
Immediately after Friday evening's incident the Secret Service increased foot patrols along the perimeter fence, deployed additional surveillance resources, and changed the procedures for ensuring the entrance to the building is secure, Mr Earnest said.
"The president is confident the changes will be properly implemented," he said.
The review of security was initiated by Secret Service director Julia Pierson, who also ordered "the immediate enhancement of officer patrols and surveillance capabilities" around the White House.
In July, police found two powerful rifles, four handguns and other firearms and ammunition in Mr Gonzalez's vehicle along with a White House map when he was stopped in south-west Virginia, a local prosecutor told the Associated Press news agency.
He served in the military from 1997 until his discharge in 2003, and again from 2005 to December 2012, when he retired due to disability, the AP reported.
Family and friends told the Washington Post Mr Gonzalez was suffering from post-traumatic stress disorder after serving as a sniper in Iraq.
An apparently unrelated incident on Saturday saw a man drive up to a vehicle gate in the complex and refuse to leave.
Secret Service agents shut down nearby streets and searched the vehicle for explosives.
Officials said Saturday's incident was an "everyday occurrence".