A Derby man has pleaded guilty to mailing letters threatening the use of anthrax against governmental agencies, federal prosecutors said Wednesday.

Amir Omerovic admitted in U.S. District Court in Bridgeport that he sent letters last October to Gov. John G. Rowland, the Judicial Review Council, the U.S. Coast Guard, the U.S. Marine Corps and other public agencies in Connecticut.

The letters referred to the Sept. 11 terrorist attacks.

“This is only the beginning,” Omerovic’s letter said. “Americans will die. Death to America and Israel.”

The letters did not contain anthrax, any white powder or other substance. Federal officials said there was no evidence Omerovic — a naturalized U.S citizen from Bosnia — had access to anthrax.

Omerovic, 28, was arrested in November. He is scheduled to be sentenced by Senior U.S. District Court Judge Alan Nevas on May 17.

He faces up to five years in prison and fines of up to $250,000.

–Associated Press