(CNSNews.com) - Far from being "contained," radical Islamic terrorists operating in Syria are "expanding globally and plotting aggressively," Homeland Security Committee Chairman Rep. Michael McCaul told Congress on Wednesday.
"ISIS is now responsible for more than 60 terrorist plots against Western targets, including 18 in the United States," McCaul said.
"Here at home, we have arrested more than 70 ISIS supporters over the last year. That's on average more than one per week, and the FBI says it has nearly 1,000 ISIS-related investigations in all 50 states. If this is not a war, then I don't know what is."
McCaul spoke at a joint hearing with the House Foreign Affairs Committee on "The Rise of Radicalism."
"America cannot wait for terrorists to launch their next attack," he said. "We must respond immediately. We can start by securing the homeland."
On Thursday, in an effort to close security loopholes, House Republicans plan to introduce a bill pausing the influx of Syrian and Iraqi refugees until background checks can be strengthened.
Among other things, the bill would require the heads of the FBI, Homeland Securitiy Department, and Director of National Intelligence to certify to Congress that each refugee "is not a threat to the security of the United States."
The bill does not address the religion of the refugees, but critics say it targets Muslims, since the majority of Syrian refugees are Muslim.
The White House issued a statement saying President Obama would veto the bill, because it would "unacceptably hamper our efforts to assist some of the most vulnerable people in the world, many of whom are victims of terrorism, and would undermine our partners in the Middle East and Europe in addressing the Syrian refugee crisis."
Current refugee screening includes photographs, fingerprinting, in-person interviews, and database checks -- where data exists and can be checked. Syria is not one of those places. The process takes around 18 to 24 months, the Obama administration says.
McCaul on Wednesday said his committee has just released a new report on the counter-terrorism challenges associated with Syrian refugee flows.
He said the results of the nearly year-long investigation are "sobering."
"While we are proud of our humanitarian tradition of welcoming refugees into our country, this is a special case. The president's own intelligence and law enforcement officials have warned this committee of the risk involved with the Syrian refugee program and the high-threat environment and I -- I have to take them at their word.
"I've called upon the President to temporarily suspend Syrian refugee admissions into the United States until we can improve the screening and vetting process. But we cannot wait for the president to take action. Congress will act immediately to make sure the system is more secure.
"Americans are worried about the terror threat level, and my promise to the American people is that we are working hard to strengthen this country's defenses. And my promise to our allies is that we stand ready to help you to do the same."
While Republicans concentrate on the refugee admissions, Democrats are taking a different tack: They plan to introduce a bill restricting visas for anyone who has been in Iraq or Syria in the past five years.
The Associated Press quoted Sen. Dick Durbin (D-Ill.) as calling the refugee program "serious and arduous," while the visa waiver program requires no vetting. He said it's the visa waiver program that "has to be reformed," not the refugee program.