Person jumps FBI field office fence in Chicago, throws rocks at building

A person who jumped the fence outside the FBI's Chicago field office and began throwing rocks at the building was detained later

A person jumped the fence outside the FBI's Chicago field office and began throwing rocks at the building on Thursday morning, authorities said.

No injuries were reported in connection with the incident and Rob Sperling, a spokesman for the Federal Protective Service, said that the person was detained and taken by Chicago police to a hospital for evaluation. The police department's news affairs office said the person was only taken to a hospital but was not arrested.

FBI spokeswoman Siobhan Johnson declined to comment beyond confirming that a "security incident" had occurred at about 11 am and that there were no injuries and no known threats to the public at this time."

The incident comes at a time of increased concern for the safety of federal law enforcement officers since the FBI served a court-authorized search warrant at the Florida home of former President Donald Trump. Since the warrant was served, a man armed with an AR-15 was killed in a shootout after attempting to breach FBI offices in Cincinnati, a Pennsylvania man was arrested after posting death threats against agents on social media and there have been a number of calls for armed uprisings and civil war.

In response, the FBI and Department of Homeland Security issued a joint intelligence bulletin warning about an increase in violent online threats targeting federal officials and government facilities including "a threat to place a so-called dirty bomb in front of FBI headquarters," according to a copy of the document obtained by The Associated Press.