The FBI and New York Police Department are assessing the credibility of information received about a possible al Qaida terror attack against the US on the eve of election day.
Officials said counter-terrorism investigators are reviewing the information that mentioned New York, Texas and Virginia as potential targets.
It was not immediately clear how the intelligence came to investigators' attention. An NYPD spokesman said in a statement that the information "lacks specificity".
The FBI said it was working closely with law enforcement agencies and sharing intelligence reports.
Officials say they regularly assess all possible security threats ahead of major events.
CBS News first reported the potential threat.