Republican presidential candidate and Senator Ted Cruz slammed President Obama for his plan to allow the entry of thousands of Syrian refugees into the United States, calling it an "absolute lunacy."

During a Q&A session at the Iowa Grassroots Coalition Candidate Honest Assessment Summit on Saturday, Cruz said a number of the refugees are suspected ISIS militants.

"With regard to the Syrian refugees, I think Obama's proposal to accept tens of thousands or hundreds of thousands of Syrian Muslim refugees is absolute lunacy," Cruz answered a question, according to the Examiner. "The Director of National Intelligence has told us it's very likely that among those refugees going into Europe are a substantial number of ISIS terrorists."

Cruz, Gov. Bobby Jindal and former Gov. Mike Huckabee attended the event that was moderated by New Zealand author and speaker Trevor Loudon and live-streamed at Breitbart News.

Cruz made the statement in reference to US National Intelligence head James Clapper, who warned last month about the dangers of ISIS terrorists infiltrating Western countries through the flow of migrants.

"As they descend on Europe, one of the obvious issues that we worry about, and in turn as we bring refugees into this country, is exactly what's their background? We don't obviously put it past the likes of ISIL to infiltrate operatives among these refugees. That is a huge concern of ours," Clapper said, according to the Washington Times.

Cruz took exception to Christians who are being persecuted by ISIS, saying the US needs to "stand up as a refuge and safe haven for Christians being persecuted by monsters like ISIS."

He said the case of Christians being persecuted in the Middle East is a "very different circumstance."

"Middle Eastern Christians are being persecuted...they are facing genocide," he said, adding that there is "no reasonable threat of terrorism" from among Christians.

During a recent US House Judiciary Hearing, FBI Director James Comey said it will be a challenge to confirm the identities of the refugees.

"The only thing we can query is information that we have," Comey said. "So if we have no information on someone... there will be no record of them... so it will be challenging."

Cruz said, "If you look at the current refugee wave which is flowing into Europe ... one estimate was that 77 percent of those refugees are young men, which is a very unusual demographic for refugees."