A homeless man who triggered a security alert when he jumped a White House fence and ran into the building with a knife had 800 rounds of ammunition in his car, a court has been told.

Former US Army soldier Omar Gonzalez, 42, was arrested on Friday after he evaded the outer layer of security around the US presidential residence and made it inside before being tackled.

“Mr Gonzalez’s preoccupation with the White House and accumulation of a large amount of ammunition … renders him a danger to the president,” US prosecutor David Mudd said on Monday.

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In addition to the ammunition, found in a car parked near the White House, investigators uncovered two hatchets and a machete.

Mudd made no mention of any firearms.

The prosecutor told the court that the suspect was already facing charges in the US state of Virginia over an illegal sawn-off shotgun found in his vehicle.

On that occasion, Mudd said, he was also found in possession of a map with the locations of the White House and of a Masonic temple in the Washington DC suburbs circled.

Meanwhile, President Barack Obama has praised the Secret Service for doing “a great job”.

While signing a declaration promoting service for children in need, Obama said he was grateful for the “sacrifices” the service performed on his behalf and on behalf of his family.

The Secret Service has launched a review of security practices in the wake of the incident.