ISIS Could Infiltrate Refugee Pipeline to US, General Says

The United States should be wary of the potential for ISIS operatives to infiltrate the flow of refugees into the West, Gen. John Allen, the president's top envoy on the coalition to defeat ISIS, told ABC News today.

"I think we should watch it. We should be conscious of the potential that Daesh may attempt to embed agents within that population," Allen said in an interview with Chief Global Affairs Correspondent Martha Raddatz, using another common moniker for the terror group.

But Allen was quick to say that he's confident in the FBI and Department of Homeland Security's abilities to defend against such threats. "I have confidence that they'll work very, very hard to prevent them from getting into the country," Allen said.

The White House said Thursday it wants to increase the number of Syrian refugees it takes in next year, from 1,500 so far in 2015 to roughly 10,000 in fiscal year 2016, which starts Oct. 1.

Syrian refugees are pouring into Europe at alarming rates. Germany had committed to take in 500,000 of them. Many of them are fleeing ISIS, but most are trying to escape military attacks from Syria's brutal dictator, Bashar Assad.

Although Gen. Allen attributes much of the violence to Assad, he maintains that Syria's problems can't be solved militarily and that Assad must be removed within the political process.

Allen also pointed to recent success in Syria. "There has been enormous progress in pushing Daesh off the border of Syria and Turkey ultimately to close that border," he said, "to prevent the flow of foreign fighters."

More of the interview with Gen. John Allen will appear this Sunday on ABC News' "This Week with George Stephanopoulos."