The conservative rock guitarist and spokesman for the National Rifle Association -- in a video posted by the NRA on YouTube -- said, "If Barack Obama becomes the president in November again, I will either be dead or in jail by this time next year."
"We are aware of it, and we'll conduct an appropriate follow up," the Secret Service said in a statement, New York magazine reported Tuesday.
Nugent, who has endorsed Mitt Romney for president, said administration officials including Vice President Joe Biden, Secretary of State Hillary Clinton and Attorney General Eric Holder are "criminals." He said the government has been "wiping its ass with the Constitution" and called on voters to "ride into that battlefield and chop (Democrats') heads off in November," CNN reported.
"If you can't go home and get everybody in your lives to clean house in this vile, evil America hated administration, I don't even know what you're made out of."
The Romney campaign issued a statement saying "divisive language is offensive no matter what side of the political aisle it comes from," The Christian Science Monitor reported.
White House press secretary Jay Carney said the president has said "we can't be policing the statements of supporters across the board."
"The president is focused on the issues. The president is focused on doing everything he can specifically with regards to helping the economy grow and helping the economy create jobs," Carney said.
Democratic National Committee Chairwoman Debbie Wasserman, a Florida congresswoman, called on the Romney campaign to denounce Nugent's remarks, which she called "despicable, deplorable and completely beyond the pale."