'If You See Something, Say Something': Authorities Step Up Security Globally After Manchester Bombing

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In the wake of Monday's deadly bombing in Manchester, England, security has been beefed up at high-profile sites across the U.S.

Read: Videos Show Chaos in Aftermath of Bombing at Ariana Grande Concert in Manchester

Counter-terrorism officers were everywhere at Times Square and other key locations in New York City.

"At this time, we have no information to indicate a specific credible threat involving music venues in the United States," the Department of Homeland Security said in a statement. "However, the public may experience increased security in and around public places and events as officials take additional precautions."

Former NYPD Detective Wally Zeins spoke to Inside Edition about why terrorists are choosing soft targets like a concert venue.

“The venue they picked, they knew they couldn’t get inside because of the security,” he told Inside Edition. “This was still a very soft target with over 20,000 people and as people were leaving, they were running to the subway. He was able to get the most tragic damage to the people coming down.”

The bombing at the Ariana Grande concert at Manchester Arena comes as the summer concert season is about to launch in New York City.

Billy Joel, Paul McCartney, Justin Bieber, U2, Kendrick Lamar, and Tom Petty are just some of the A-list acts performing in the city and in the metropolitan area in major venues like Madison Square Garden.

Read: 8-Year-Old Named Among Victims As Ariana Grande Says She's 'Broken' After Bombing Kills 22

So how can concertgoers stay safe?

“What is so important is that everyone has to work together,” Zeins advises. “If you see something, say something.”

Terrorism experts say targets like concerts are a hallmark of ISIS. Previous targets include Le Bataclan concert hall and the national soccer stadium in Paris, an airport in Brussels, a soccer stadium and record store in Istanbul, the boardwalk in Nice, France, as well as a nightclub in Orlando.

Watch: Sweden on Edge Following Beer Truck Terror Attack: 'The Mood Is Very Somber'