NEW YORK (CBSNewYork/AP) — A post on an online message board for Islamic State sympathizers encourages would-be terrorists to attack tourist hot spots in the United States, — and Times Square is the top target.

The post is titled “To the Lone Wolves in America: How to Make a Bomb in Your Kitchen, to Create Scenes of Horror in Tourist Spots and Other Targets.” It includes bomb-making instructions and a list of ingredients, even how to pack it with shrapnel, WCBS 880’s Rich Lamb reported.

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Other American tourist spots are also on the threat list, including the Las Vegas Strip.

“This is a new world, if you will, or the evolving world of terrorism, and we’re staying ahead of it,” NYPD Commissioner Bill Bratton said Tuesday. “We’ve been focused on it, and I believe that we are as prepared as any entity could be to deal with the threats.”

As CBS 2 Political Reporter Marcia Kramer reported, the threat now has the NYPD more worried than they ever were about al Qaeda.

“We are quite concerned, as you would expect, with the capabilities of ISIS much more so than al Qaeda,” Bratton said.

The post on the ISIS message board detailed how to use Christmas tree lights, bleach, sugar, matches, and clocks to build homemade bombs in America.

A similar explosives recipe was used in the Boston Marathon bombing in April 2013. The ISIS post includes instructions for pressure-cooker bombs like the ones used in Boston.

It is the new and improved use of social media by ISIS that has officials in New York City on alert.

The post about the bomb-making threat surfaced three weeks ago. But it was posted again on Saturday afternoon – around the same time that ISIS used the same site to release the video of British aid worker David Haines’ beheading.

Experts believe ISIS propagandists were hoping the stunning video would help recruit American supporters.

On Monday, Mayor Bill de Blasio, New York Gov. Andrew Cuomo and New Jersey Gov. Chris Christie met in Manhattan with U.S. Homeland Security Secretary Jeh Johnson to discuss ways to secure the region from what they described as a mounting terror threat fueled by Islamic State extremists.

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The officials emerged from the meeting saying they would develop a coordinated security plan covering both states.

The session came a week after President Barack Obama told the country he is authorizing stepped-up airstrikes in Iraq and Syria against Islamic State militants.

“We’re increasingly concerned about domestic-based potential acts of terrorism, particularly as groups overseas become more sophisticated in their own propaganda,” Johnson said.

Officials are worried that the terrorist propaganda machine will create local lone wolves, Johnson said.

“We would be in a state of denial if we did not say, with what’s going on internationally, that the risk of a threat to us has increased,” Cuomo said Monday.

“As New Yorkers, we know our city is the No. 1 terror target,” de Blasio added.

Bratton said Tuesday that he is also worried about Americans currently fighting with ISIS.

“The potential for them to try to come back and commit terrorist attacks here are very real, and it has expanded significantly the terrorist threat,” Bratton said.

In response to one post on the ISIS message board, one user asked how to maximize the number of people killed or injured by the bombs.

Other posts urged the targeting of Jews, Zionists, Freemasons, and “angry blacks” – possibly a reference to those upset with the Eric Garner case on Staten Island or the police shooting that killed Michael Brown in Ferguson, Missouri, Kramer reported.

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