Santa Monica Courthouse (File by Daniel Archuleta)

Authorities responded to a bomb threat at Santa Monica Courthouse after a suspected explosive device was reported Wednesday afternoon.

Sheriff’s bomb squad personnel arrived around 1 p.m. at the court, which is located on Main Street near Olympic Drive. The squad was seen entering and exiting the building within a few minutes, after which a robot was deployed. The robot entered the courthouse and detonated the device at about 2 p.m.

Officials then found an unknown substance in the area, prompting Santa Monica firefighters to analyze the potentially hazardous materials.

Santa Monica police were at the scene to assist with traffic and security. Road closures remained in effect in the area, including on Main Street between Pico Boulevard and Colorado Avenue.

Additional details were not immediately available.

The courthouse, located at 1725 Main St., is close to City Hall and police headquarters as well as the Civic Auditorium and Santa Monica High School.

Santa Monica’s courthouse was temporarily closed in December as authorities responded to a report of a suspicious package.

In March, a suicidal man who had driven onto the courthouse lawn prompted the temporary evacuation and closure of the building.

Updates to follow.