WASHINGTON: A man suspected of attempting to assassinate Donald Trump was charged with two gun-related crimes in federal court on Monday, a day after being spotted with a rifle hiding in the bushes at the former US president’s golf course in Florida.

More charges appear likely, but the initial counts - possession of a firearm as a convicted felon and possession of a firearm with an obliterated serial number - will allow authorities to keep him in custody as the investigation continues.

The Republican presidential candidate in the Nov. 5 election was unharmed. But the incident raised fresh questions about how an armed suspect was able to get so close to him, just two months after another gunman fired at Trump during a July 13 rally in Butler, Pennsylvania, grazing his ear with a bullet.

Phone records suggest the suspect may have been lying in wait for nearly 12 hours on Sunday, according to a criminal complaint.

The US Secret Service opened fire after an agent saw a rifle barrel poking out of the bushes on Sunday at Trump’s golf course in West Palm Beach, a few hundred yards away from where the former president was playing.

The gunman fled in a sports utility vehicle, according to the complaint. Officers found a loaded assault-style rifle with a scope, a digital camera and a plastic bag of food left behind.

A suspect, identified on Monday as Ryan Routh, 58, was arrested about 40 minutes later driving north on Interstate 95. When asked if he knew why he had been stopped, Routh “responded in the affirmative,” according to the complaint. The license plate on his vehicle had been reported stolen from another car.