Feinstein: U.S. Terror Attacks 'Not Out of the Realm of Possibility'

Terror attacks are not only a threat for Europe, but in the United States as well, Sen. Dianne Feinstein said Sunday, as there are also sleeper terrorist cells in the United States.

While the California Democrat, who is the top Democrat on the Senate Intelligence Committee, told CNN's "State of the Union" that while  there is not credible information pointing to a specific plot, it is "not out of the realm of possibility" that one could occur.

It will call for vigilance and making sure national security is prepared in order to prevent attacks, Feinstein said.

"The French are good at it; so are the British and the Germans," she said. "Hopefully we can be even more active in terms of doing those things that will help us to find terrorists, see who they're communicating with in this country, and to track that."

But still, tracking terrorists is difficult, she admitted, noting that the French had the three men who carried out the attacks on the satirical weekly Charlie Hebdo and the subsequent hostage situations under surveillance for some time.

"I don't know whether they've had cutbacks or what," she said. "The way you stop this is intelligence."

Feinstein also spoke out against a visa waiver program, which allows citizens from some countries, including France, to stay in the United States for up 90 days without a visa.

"It is the Achilles heel of America," Feinstein said. The suspects in last week's attack were all French citizens, and even though they were all on a no-fly list, they could have gotten a false passport and entered the United States, as French citizens can come in without a passport.

Terrorists can, through the visa waiver program, "come back from training, they go through a visa waiver country, and they come into this country," Feinstein said. "We have a big problem here."

Meanwhile, Feinstein said there is also a problem with propaganda materials and bomb-making directions circulating freely online, and has proposed legislation that would punish those who make the information available if they know the information will be used for an attack.

"We know the people who put it there [on the Internet] intend to have it used for a terror attack," she said. "If your material s going to be used for an attack...When you have a recipe for a very serious bomb out there on the Internet, you have to deal with it. The people who put it there intend to have it used for a serious attack."

In Yemen, Feinstein pointed out, there is still "a very serious bomb maker still alive," and information is being released that includes targets lists, planes to bomb, where to sit on an airplane to do the most damage, "and this material circulates freely through the Internet."

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