(CNSNews.com) - Unlike the al Qaida terrorists of 15 years ago, the "new generation" of Islamic extremists has an instant global reach, Rep. Michael McCaul, (R-Texas), chair of the House Homeland Security Committee, told "Fox News Sunday."
Host John Roberts asked McCaul to compare what's going on right now in Syria and Iraq with what was going on in Afghanistan before the 9-11 attacks on America.
"Well, pre-9/11, bin Laden operated in caves and couriers, primitive communications," McCaul responded. "Now, we have a new generation of terrorists that know how to use the Internet, know how to exploit it, used it to recruit.
"They've recruited 40,000 foreign fighters, largest convergence that we've seen of jihadists in what is now called the caliphate, and that's due to the Internet.
And so they are expanding their bandwidth in a global sort of jihad movement.
"That's what really concerns me about the modern day terrorists that we face, is this global expansion."
McCaul said the US. is having "limited success" in Iraq and Syria, where some 5,000 U.S. troops are now advising and assisting Iraqi ground fighters. But occasionally, those American troops are being drawn into combat themselves.
McCaul also pointed to the flow of some 6,000 ISIS fighters (his estimate) into Libya: "Libya is a failed state and becoming a launching pad for external operations, as is Sinai in Egypt where we see ISIS that pulled off the Sharm el-Sheikh.
ISIS claimed responsibility for placing a bomb on a Russian passenger jet that crashed last October shortly after take-off from the Egyptian resort of Sharm el-Sheikh, killing all 224 passengers and crew on board.
ISIS also has migrated to Afghanistan.
Earlier this month, a U.S. military spokesman estimated there are "somewhere between 1,000 and 3,000" Islamic State fighters in eastern Afghanistan.