Sen. John McCain (R-Ariz.) is “very worried” about Thursday’s federal appeals court decision that struck down the National Security Agency’s bulk collection of American’s phone records, he said Thursday on Fox News’s “America’s Newsroom.”

“We have to have the ability to monitor these communications,” he said.

“It’s pretty clear that 9/11 could have been prevented if we had known about some of the communications that were linked to those who committed the terrible atrocity of 9/11.”