An hours-long standoff with an armed suspect who tried to breach the FBI’s field office in Cincinnati on Thursday has ended, according to Clinton County Emergency Management Agency.

The Columbus, Ohio man died of his injuries after exchanging fire with police, authorities said. The identity of the suspect has not been revealed. The motive behind the incident also remains unknown.

The armed man tried to enter the FBI office Thursday morning around 9:15 a.m. ET, Lt. Nathan Dennis, a spokesperson for the Ohio State Highway Patrol. He was unsuccessful in breaching the office. However, he fled the area soon after.

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An Ohio state trooper spotted the suspect’s vehicle at a northbound rest stop along Interstate 71 just 20 minutes after the attempted breach. The trooper tried to initiate a traffic stop before the suspect fled.

The man exchanged gunfire with police officers after fleeing from the building.

“The suspect vehicle did fire shots during that pursuit… Gunfire was exchanged between officers on scene and the suspect,” Dennis said, adding that there is no risk to the public outside the immediate area.

A federal law enforcement source told CNN the suspect was likely carrying a nail gun and AR-15.

Two law enforcement officials close to the matter told the New York Times that investigators are looking into whether the man had ties to extremist groups, including one that participated in the Jan. 6 attack on the Capitol.

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The FBI confirmed the incident, saying that an armed subject attempted to breach the facility’s Visitor Screening Facility.

“Upon the activation of an alarm and a response by armed FBI special agents, the subject fled northbound onto Interstate 71,” the statement said. “The FBI, Ohio State Highway Patrol, and local law enforcement partners are on scene near Wilmington, OH trying to resolve this critical incident.”