Intelligence sources say that three states could be targets on Monday.
Officials have warned Al Qaeda could be planning terror attacks around the US Presidential election.
The FBI and the New York Police Department said they are taking the threat seriously and are assessing the credibility of a possible attack on the eve of Election Day.
Officials said counter-terrorism investigators are reviewing the information that the militant group is planning to strike in New York, Texas and Virginia, although there have been no specific locations mentioned.
New York officials confirmed they have been made aware of a potential threat.
A source said that the Port Authority of New York and New Jersey, which operates airports, tunnels and bridges around New York City had been alerted.
Armed officers are patrolling in Times square, New York.
The threat comes just four days before polls officially open in the US, ending the race for the White House between Hillary Clinton and Donald Trump.
Officials said they regularly assess all possible security threats ahead of major events.
“The counter-terrorism and homeland security communities remain vigilant and well-postured to defend against attacks here in the United States.”, said a Senior FBI official.
“The FBI, working with our federal, state and local counterparts, shares and assesses intelligence on a daily basis and will continue to work closely with law enforcement and intelligence community partners to identify and disrupt any potential threat to public safety.”
Al Qaeda, and its now deceased leader Osama bin Laden, was behind the 11 September 2001 attacks on the US, which killed nearly 3,000 people.