I'm worried about ISIS threat in US: Scott Walker

Gov. Scott Walker: How to keep America safe
Gov. Scott Walker: How to keep America safe   

The United States may need to use ground troops in the fight against Islamic State, Wisconsin Gov. Scott Walker told CNBC on Thursday.

"Whether it's special ops or other engagements out there, we've got to be prepared to do what it takes to keep America safe," the potential 2016 GOP presidential candidate said in a "Squawk Box" interview.

Walker said he receives regular threat assessments and worries about the possibility of radical Islamist terrorism not just in the Middle East, but in the United States and around the world.

"Obviously we've seen [it] in Europe. We most notably saw what happened in France. It's not a question of if there's another attempt on American soil again, it's when," he said. "I think we need aggressive leadership to take the fight to them instead of waiting for it to come to us."

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The country must also step up its coordination with allies in Europe, Israel and Japan while also looking for support from nations in the Middle East.

"You look at Jordan, Turkey, Saudi Arabia, others who are not traditional military allies, I think they see a vested interest in taking on radical Islamic terrorists right now," he said.