A supporter of President Donald Trump pleaded guilty on Thursday to mailing crude bombs to prominent Democrats including former president Barack Obama and former Democratic presidential nominee Hillary Clinton.
Cesar Sayoc, 57, who was arrested in Florida in October, pleaded guilty to 65 counts and could face life imprisonment at his sentencing in September.
Appearing in court in a blue prison jumpsuit, and with his hair pulled into a gray ponytail, he apologised for his actions during an appearance in a US District Court in New York.
Reading a statement prepared with his lawyers, he admitted he fashioned the homemade devices from materials including plastic piping, a digital alarm clock with electric wiring attached, fireworks and glass fragments.
"I know these actions were wrong and I am sorry," he told the court, in a barely audible, choked voice.
The slew of charges relates to 16 package bombs Sayoc sent from a Florida post office to leading Democrats as well as the Manhattan offices of CNN.
Besides Obama and Clinton, those targeted included billionaire George Soros, former president Bill Clinton, former vice president Joe Biden, actor Robert De Niro and several Democratic lawmakers, including 2020 presidential hopefuls Cory Booker and Kamala Harris.
None of the packages exploded and most did not come anywhere near their intended recipients.
"Our democracy will simply not survive if our political discourse includes sending bombs to those we disagree with," said General John C. Demers, Assistant Attorney for the National Security Division, following the hearing.
"I applaud the efforts of so many in our law enforcement community whose alertness and tirelessness led to the prompt arrest of the defendant."
Sayoc had initially been charged with 30 counts, already putting him at risk of life in prison. His guilty plea does not guarantee a more lenient sentence -- but Judge Jed Rakoff stressed he did not have to hand down a life sentence in September.
A former strip club manager and bodybuilder and martial arts practitioner, Sayoc was an ardent supporter of Trump, who has rejected accusations that his rhetoric fuels extremism.
Sayoc, who lived in a white truck plastered with pro-Trump and anti-Democrat stickers, was arrested in Florida five days after the first device was discovered in Soros's upstate New York mailbox.
The episode heightened political tensions in the lead-up to the November 6 US midterm elections, which saw Democrats gain control of the House of Representatives while Republicans retained control of the Senate.
Police found Sayoc's fingerprints and DNA on the packages.
Sayoc has a criminal record dating back to 1991, peppered with convictions for theft, fraud, violence and a threat to blow up his electric utility company.