Police Commissioner Ray Kelly says a computer graphic warning that al-Qaida will return soon to New York City "reminds us that New York is still very much on their minds."
Kelly said Tuesday that NYPD intelligence officers and federal authorities recently became aware of the graphic, which was posted on a radical overseas website. It shows the city skyline and reads: "Al Qaeda Coming Soon Again in New York."
Officials said the graphic appeared on a site that has hosted al-Qaida material before and is what the NYPD Intelligence Division refers to as a "Category 1" website, meaning it is heavily used by jihadi and al-Qaida adherents.
Kelly said this particular site is a known propaganda site for "anti-American material, what we consider to be terrorist-related material."
He said the posting is not tied to any specific threat.
"There's nothing operational about this but obviously it's cause for concern," Kelly said.
An FBI spokesman said agents are also investigating.
Also Tuesday, the NYPD said it would beef up security at synagogues and other Jewish sites for Passover. Kelly said that response was not related to the al-Qaida posting.
Get the latest from NBC 4 New York anytime, anywhere. Follow us on Twitter, Facebook and Google+. Sign up for email newsletters here. Get breaking news delivered right to your phone -- just text NYBREAKING to 639710. For more info, text HELP. To end, text STOP. Message and data rates may apply.