SAN FRANCISCO (CBS SF) — A person of interest was detained Thursday in connection with an incendiary device that was ignited at the San Francisco Hall of Justice, leading to a brief evacuation and the cancellation of court hearings for the rest of the day, according to authorities.

The San Francisco Fire Department tweeted about a fire at the Hall of Justice at about 11:30 a.m.

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Police later confirmed that small explosion from the incendiary device was reported around 11:10 a.m. The device was set off in the building’s lobby on the ground floor of  850 Bryant St., San Francisco police spokeswoman Officer Grace Gatpandan said.

A person of interest was detained in connection with the device.

No injuries were reported but the building was evacuated and remained closed as of 1 p.m. while authorities investigate, Gatpandan said.

The all-clear was given at 1:38 p.m. and people were allowed back inside, she said.

The investigation into the incident led officials to cancel court sessions for the remainder of the day.