A man carrying a pistol and two live cartridges was apprehended at Gate No 3 of the Parliament House in New Delhi on Tuesday afternoon, police said.
Rajesh Rathore, aged about 30, was immediately taken for a joint interrogation by intelligence agencies and police, they said.
Preliminary investigations revealed that Rathore hails from Baroda in Gujarat and had arrived in Delhi on Tuesday from the Jammu Express train, Deputy Commissioner of Police (New Delhi district) Manoj Lall said.
Married with three children, Rathore -- a driver -- seems to be a vagabond, he said.
He had allegedly had a fight with his family members and was thrown out.