(NEXSTAR) – The driver of a delivery vehicle was arrested by U.S. Capitol Police on Friday morning after an assault rifle was found in the back seat of a truck he was driving.

Maryland resident Michael J. Donahue, 57, is now facing possible charges, including possession of an unregistered firearm, possession of unregistered ammunition and unlawful activity, according to a news release from U.S. Capitol Police.

Authorities said Donahue was the driver of a Ford pickup truck that had arrived before 5 a.m. to be screened at “an off-site delivery facility,” which is used by Capitol Police to inspect delivery vehicles before they are allowed to proceed to Capitol Grounds.

In the back seat, covered partially by a blanket, was an assault rifle manufactured by Tippmann Arms, a representative for the Capitol Police told Nexstar. The screening team also found an extended magazine for the rifle in the trunk. The gun was confiscated “before it reached Capitol Hill,” according to the news release.

Police say they do not believe Donahue was planning to target the Capitol buildings.

“Still, this serves as yet another reminder that all weapons are prohibited from Capitol Grounds,” USCP Chief Tom Manger said in a quote included with Friday’s news release. “I thank our entire team at the off-site screening facility [for] stopping this gun before it came anywhere near the U.S. Capitol Complex.”

Donahue’s charges are pending court proceedings. If guilty, such offenses can be punishable by fines, imprisonment or both, according to the Capitol Police.

The Capitol’s rules for prohibited items extend to not only guns but knives, explosives, stun guns, pepper spray, razors and slingshots, among multiple other types of “weapons or devices.” Even certain “pointed objects” like letter openers or other sharp objects deemed to be a threat are prohibited from Capitol grounds or visitors’ areas.

“While this may be a small inconvenience, planning ahead by leaving these items at home will allow for an expeditious security screening process,” the Department of the U.S. Capitol Police says on its website.