National security expert Juliette Kayyem says the country of origin for the attacker in New York illustrates a problem with the way President Trump is addressing counterterrorism policy.

"President Trump has a focus on countries, and what you see in this process is none of this is country-based," she said on Boston Public Radio today. "There's a disjoint between what happened yesterday and the policy prescriptions that are coming out of the White House."

The perpetrator of yesterday's attack, Sayfullo Saipov, is a 29-year-old immigrant from Uzbekistan. He drove a car into a crowd of people in Lower Manhattan, killing eight.

Uzbekistan has not been targeted by Trump's counterterrorism policy, like the so-called 'travel ban' that barred travel from several Muslim-majority countries.

Kayyem said she was hesitant to draw connections between Saipov's radicalization and terrorist activity inside Uzbekistan.

"Unless you're going to show me strong ties to something going on in Uzbekistan, I'm not quite sure that's an explanation," she said.

Kayyem explained Saipov has been living in the United States since 2010, and said he was radicalized domestically.

"There [are] no signs of foreign travel or foreign training," she said. "He has been planning it for months."

National security expert Juliette Kayyem is the host of the SCIF podcast, CEO of ZEMCAR, founder of Kayyem Solutions and contributor to WGBH and CNN. To hear her interview in its entirety, click on the audio player above.