A man has been detained following an explosion at the Santa Maria courthouse in California, where he threw an explosive device during his arraignment.

The suspect, 20-year-old Nathaniel McGuire, injured three individuals in the blast, which occurred around 8:48 a.m.

Local law enforcement, including Santa Maria Police and Santa Barbara Sheriff's deputies, responded swiftly to the scene.

While three individuals sustained burns and were treated at a hospital, none of the injured were courthouse employees.

McGuire attempted to flee the scene but was apprehended outside the courthouse, wearing body armor.

A search of McGuire's vehicle revealed multiple weapons, including a shotgun, a rifle, ammunition, a suspected bomb, and ten Molotov cocktails.

The FBI is assisting in the investigation, which indicates that McGuire may have acted out of a personal grudge linked to a recent firearms arrest.

Authorities believe the courthouse attack is related to McGuire's previous arrest for firearms violations and is not considered a terrorism act.

McGuire faces multiple felony charges, including attempted murder and possession of explosive devices, and is currently being held without bail.

Officials have confirmed that there is no ongoing threat to the community, emphasizing that McGuire's actions stemmed from personal grievances.

California Governor Gavin Newsom's office is monitoring the situation, coordinating with local law enforcement as investigations continue.

Nearby buildings, including a school, were evacuated as bomb squad officials searched for additional explosives in the area.