The FBI arrested a northern California man Wednesday for allegedly making threatening phone calls to House Speaker Nancy Pelosi over health care reform, law enforcement officials told Fox News.

Gregory Giusti will appear in federal court Thursday morning when bail will be discussed, the FBI told Fox News. 

"We take these threats against public officials very, very seriously!" an FBI official told Fox News.

It has not yet been determined whether Giusti's court appearance on Thursday will be an arraignment.

Several federal officials said the man made dozens of calls to Pelosi's homes in California and Washington, as well as to her husband's business office. They said he recited her home address and said if she wanted to see it again, she would not support the health care overhaul bill that since has been enacted.

One official said the man is believed to have spoken directly with Pelosi at least once.

The officials spoke on condition of anonymity because they were not authorized to discuss the case publicly.

Brendan Daly, a spokesman for Pelosi, said the speaker thanks all the law enforcement officials "for their professionalism in this matter."

"She will have no further comment at this time," Daly said in a written statement.

On Tuesday, authorities announced charges against a Washington state man who allegedly made threatening calls to Sen. Patty Murray, a Democrat. Charges also have been filed against a Philadelphia man who allegedly made a YouTube video threatening Rep. Eric Cantor, R-Va.

Fox News' Adam Housley, Chad Pergram and The Associated Press contributed to this report.