WASHINGTON (AP) — Investigators found more than 800 rounds of ammunition, a machete and two hatchets in the car of the former soldier accused of scaling the White House fence and sprinting inside while carrying a knife, a federal prosecutor said Monday. President Barack Obama was “obviously concerned” about the weekend incident, a spokesman said.

The Secret Service increased security around the famous grounds on Pennsylvania Avenue in the nation’s capital, some guards openly holding weapons, others escorting dogs. There was talk of expanding the security zone beyond the current area as a major investigation began into the question of how the man managed to get to the building without being stopped.