04 April,2012 08:45 AM IST | | Agencies
The New York Police Department and FBI discovered the amateur graphic on the Internet on Monday.
Investigators are nowu00a0trying to determine if the message is a credible threat or a sick taunt, although so far there is no evidence that the warning is genuine.
Terror threat? The graphic was discovered on several Arabic-language websites, which is now being investigated by the FBI and NYPD
The image shows the Manhattan skyline at sunset with Al Qaeda in bold type followed by Coming Soon Again in New York.
NYPD spokesman Paul Browne said the post has appeared on a number of overseas, Arab language websites.
Police reportedly believe it was posted by an Egyptian writer who regularly uses the Internet to spread propaganda about the terror network.
The site had the graphic on its artwork and design page.
Browne added: "We've done an analysis. He's not an American. We're leaning toward (him being) an Egyptian, using Arabic, to create communications on this site."
FBI spokesman J Peter Donald said that the agency's Joint Terrorism Task Forceu00a0is aware of the posting and is investigating.
He added, "The FBI takes all threats seriously and thereu00a0is no specific or credible threat to New York at this time."
The finding comes asu00a0al-Qaeda was dealt a blow after a number of the terror organisation's web forums were shut down in an apparent cyber attack.
Five al-Qaeda websites promoting a jihad or holy war against the West have been offline for almost two weeks.
Al-Qaeda has been blamedu00a0in the September 11, 2001,u00a0terrorist attacks, which destroyed the World Trade Centre and killed several thousand people.
