Violent extremists and others may be planning further retaliatory attacks in response to the attempted assassination of Trump at a Pennsylvania rally.
The FBI and Department of Homeland Security remain concerned about the possibility of retaliation following the attack at Trump's rally on July 13.
Individuals in some online communities threatened or hinted at acts of violence in response to the attack, Politico reported, citing a document from the services.
The intelligence bulletin said election-related targets were at heightened risk of attack.
Repeated or retaliatory attacks in response to the assassination attempt on Donald Trump could be carried out by violent extremists and others.
The intelligence warning comes amid a situation that US authorities have identified as a heightened threat.