A San Diego man accused of leaving a threatening voice mail at the office of a Muslim civil rights organization pleaded guilty Tuesday to felony charges.

John Weissinger entered his guilty plea in San Diego Superior Court to felony charges of making a criminal threat and illegal possession of an assault rifle, and a misdemeanor hate crime charge.

Weissinger, 53, left a threatening voice mail at the office of the San Diego chapter of the Council on American-Islamic Relations, known as CAIR-San Diego, prosecutors said.

According to the prosecution, Weissinger said in his voice mail that he had a lot of firepower and that the massacre at the Charlie Hebdo office in Paris could occur again. Weissinger also was accused of sending a threatening email on Jan. 15 to CAIR's office in Washington. Prosecutors said police found an AR-15 rifle and a high-capacity magazine at his home.

"Unfortunately there are people like that, and we need to make sure they get a clear message that this is not acceptable," said Hanif Mohebi, the executive director of CAIR-San Diego.

Weissinger told KNSD-TV shortly after his arrest in January that he had been drinking while watching news of the terror attack by Islamic extremists on satirical newspaper Charlie Hebdo and a kosher grocery that left 20 people dead, including the three attackers. He told reporters he later regretted his actions.

Neither Weissinger nor his attorney could be reached for comment Tuesday.

Sentencing is scheduled for October 13.