National intelligence director Mike McConnell said Tuesday that US authorities are worried about "sleeper cells" of would-be terrorists inside the United States and are remaining vigilant against any new attacks.
On the sixth anniversary of the attacks that killed nearly 3,000 people in New York, Washington and in western Pennsylvania, McConnell also said plots against the United States have been thwarted. But he said there can be no safety guarantees.
"We're safer but we're not safe," he said in an interview on ABC's "Good Morning America."
Join Jerusalem Post Premium Plus now for just $5 and upgrade your experience with an ads-free website and exclusive content. Click here>>