COLUMBUS, Ohio (WCMH) — A man who set off an hours-long standoff with the FBI and law enforcement after he walked into a field office Thursday with an assault rifle has been killed.

Around 9:15 a.m., the FBI said the suspect — who NBC News identified as Ricky Walter Shiffer — set off an alarm at its visitor screening facility in the Cincinnati area. NBC reported Shiffer fired a nail gun at law enforcement personnel and held up an assault rifle before fleeing in a vehicle.

A chase ensued onto I-71 North. The Ohio State Highway Patrol said the man’s vehicle, a Ford Crown Victoria, was spotted by a trooper in Warren County about 9:35 a.m. The trooper attempted to pull him over but said the man opened fire multiple times.

The pursuit continued into Clinton County, where the man exited at State Route 73 and then turned onto Smith Road before coming to a stop near where the road goes over I-71. Around 3:30 p.m., more gunfire was exchanged with responding agencies, which included the FBI and troopers.

The standoff was declared over about 4:30 p.m. by the Clinton County Emergency Management Agency. After unsuccessfully using “less than lethal” force, law enforcement shot and killed Shiffer, authorities said.

Watch: 1:30 p.m. update from the Ohio State Highway Patrol

Shiffer was at the U.S. Capitol building during the insurrection on January 6, 2021, NBC reported.

NBC News reported that the FBI has been receiving heightened threats in the days since it raided the residence of former President Donald Trump but that no motive has been established in this case.

I-71 was closed until about 3 p.m. Sections of State Routes 73 and 380 were closed as well, and a lockdown was issued for the area.