Mike Rogers: The Battle Will Come to America

House Intelligence Committee Chairman Mike Rogers warned Sunday that, if the militants taking control of a vast swath of Syria and Iraq are not stopped, they will bring the battle to America and Europe.

"This is as dangerous as it gets," Rogers said on "Fox News Sunday," saying that the members of the Islamic State of Iraq and Syria are not mere "monkey-bar terrorists" training in the desert for a small-scale attack. They are "seasoned combat veterans" and will strike New York City or Washington, D.C., if given the chance, he said.

Thousands of Westerners, including Americans, are fighting in Iraq and eastern Syria and Iraq, he said, and they are being trained by ISIS to return to Europe and the United States and wage terrorism.

They have said they want to do "external operations" and know they have "Westerners who have come to Jihadist Disneyland in eastern Syria that we can further radicalize, train and send back to Europe, and send back to the United States," Rogers said.

Already, he noted, an American has been used as a suicide bomber.

Rogers said the United States must re-engage with the Arab League, which has been willing for almost three years to partner in operations to fight al-Qaida.

"They have been forgotten in this, what is really lack of decision," Rogers said, referring to President Barack Obama's announcement he would need several days to weigh options of a U.S. response.

Without a decision, the United States is allowing an "ecosystem of terrorism" to live, he said.

ISIS has taken over several cities, including Mosul and Tikrit, and was headed to Baghdad, but has slowed that effort, possibly to regroup, Rogers said.

The United States has sent the aircraft carrier USS George H.W. Bush into the Persian Gulf, but Rogers stressed a partnership with Arab League special forces.

"If we've learned anything, you can't fire missiles and then turn around and come home," he said.