Experts debated what security measures should be taken, after an attack at Istanbul's Ataturk airport left at least 28 people dead and dozens injured . Tuesday's attack was the latest in a spate of bombings in Turkey this year.

Jayson Ahern, principal of the Chertoff Group, told CNBC that the current challenge is figuring out how to adapt to the evolving tactics of terrorists.

"We're dealing with a very adaptive adversary that continues to move and react to what moves that the government makes here in the United States," he said.

The presence of enforcement personnel has pushed terrorism efforts outside security checkpoints, so airports now need to figure out how to secure the arrivals, departure and curbside areas as well as transportation networks, according to Ahern.

It was reported that suicide bombers at Ataturk airport detonated themselves before reaching a security checkpoint in the arrivals hall.

"As you move the layers of security around, you have got to be careful about having areas where you are going to have significant numbers of people dwelling because that becomes a soft target, a target of opportunity when you're dealing with the type of adversaries that we're looking at today," Ahern said.

Ahern said, however, that in order to truly progress counter-terrorism efforts "more on the intelligence front" needs to be done, and authorities need to be "more proactive."

General Barry McCaffrey agreed, saying that "the only way you really confront this is good intelligence followed by good law enforcement."

The four-star general said that he believes "ISIS has actually been confronted fairly effectively" and that "there's a major effort underway to mitigate this threat overseas."

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