U.S. inaction in Syria has created a "cauldron of bad activity" that is breeding thousands of foreign extremist fighters to eventually launch attacks against the U.S. and Europe, according to senior U.S. lawmakers.
Rep. Mike Rogers, R-Mich., chairman of the House Intelligence committee, said Tuesday that there are more foreign fighters in Syria than there were in Iraq or Afghanistan during the U.S. wars there.
"That sheer number alone should give you pause," said Rogers, who spoke at the Foreign Policy Initiative Forum in Washington, DC.
He also cited infighting among Islamic extremist groups, some of which wish to launch foreign attacks from strongholds in eastern Syria. Al-Qaida affiliates there are advocating for patience to establish a foundation before provoking Western military response, Rogers said.
"They have developed a level of patience and strategy we haven't seen before," he said.
Syria is no longer a war zone that can once again return to a state of peace following the downfall of President Bashar Assad, he said. Western nations and their allies in the region should prepare themselves for ways to "stun the chaos that will follow when he eventually -- and he will -- leave power."
Rogers, an outspoken advocate of intervention in Syria, spoke alongside Rep. Eliot Engel, D-N.Y., with whom he has appeared in public many times in recent weeks to discuss the issue. Engel has also supported the use of direct strikes in Syria to support the efforts of the Free Syrian Army, the chief coalition of rebel fighters.
"When it's over, these people will be combat trained, combat hardened and they're going to want to go home," Rogers said of the extremists. "We are going to have a wave of individuals who are committed, who have training that we haven't seen before going to Europe, and by the way the U.S. as well."
"There are thousands of people who have come from Western nations, the U.S. and other places, who are going to go back," he added. "You cannot have a safe haven operate anywhere in the world where people are committed to acts of terrorism to advance their political agenda."
The U.S. stated after the Sept. 11, 2001 attacks that it would not allow such havens to exist again. Syria today is perhaps the largest safe haven the U.S. has seen without an ability to conduct counter operations, said Rogers.
"That should concern all of us."
The U.S., Russia, and other players in the civil war, now well into its third year, will likely meet this November for a second round of talks in Geneva, following a similar summit in July 2012.