Government officials and national security experts are warning that the U.S. is vulnerable to terrorist attacks like those carried out in Paris by the Islamic State last week.
A cell of Islamic State terrorists armed with machine guns, hand grenades, and suicide bomb vests killed 129 people and wounded hundreds in Paris last Friday.
The Paris attack was the latest in a spree of the terror group's attacks outside Iraq and Syria that have resulted in more than 500 deaths since October. An Islamic State affiliate blew up 224 people aboard a Russian airliner in October. Islamic State suicide bombings in Lebanon, Turkey, and Yemen claimed killed 150 people.
According to retired Gen. Jack Keane, the attacks indicate that the terror group is taking advantage of its safe haven in Syria and Iraq to plot attacks abroad.
"They’re comfortable with this caliphate that they have, and they’re comfortable with their base of operations in Syria, to be able to project that kind of power," Keane said in testimony on Wednesday.
"They have a lot more plans than what we’re seeing," Keane said.
The Islamic State’s recruitment on foreign fighters, including Americans, leads national security experts to fear that the group could have terrorist cells embedded in the U.S. There are a "minimum" of 250 terrorists who fought abroad and then returned to the U.S., according to Fran Townsend, former counterterrorism adviser to President George W. Bush.
In light of this threat, some, like Sen. Lindsey Graham (R., S.C.) have called for U.S. military intervention to deny the Islamic State a home base to plot attacks.
"There is a 9/11 coming, and it is coming from Syria if we don’t disrupt their operations inside of Syria," Graham said.
Others have ruled out a major ground intervention. Hillary Clinton said Thursday that sending ground troops to fight the terror group would be "a mistake," even if it pulled off a 9/11-style attack on the U.S.