(CNN) - Rep. Michael McCaul, R-Texas, reiterated his opposition to military involvement in Syria on Wednesday and raised questions about the rebel force.
McCaul, chairman of the House Homeland Security Committee, said on CNN's "Erin Burnett OutFront" that he's seen intelligence in briefings that shows half of the Syrian opposition has extremist elements.
His comments stand in contrast to numbers given by Secretary of State John Kerry, who said 15% to 25% of Syrian rebels are "bad guys."
"I just don't agree that a majority are al Qaeda and the bad guys," Kerry said last week in response to a question by McCaul at a House Foreign Affairs Committee hearing.
While the Syrian rebels are fighting the regime of President Bashar al-Assad, they're arranged in different factions, each with its own agenda, experts say. Some are allied with al Qaeda.
Syria's rebels: 20 things you need to know
Kerry argued there is a "real moderate opposition that exists."
Several lawmakers who oppose U.S. military intervention in Syria, however, have raised concerns about associating with the rebels.
By attacking Syria, the United States would be essentially siding with the opposition and therefore siding with groups like al Qaeda, some argue.
"There are no good sides in this war, no good options," McCaul said. "I don't think we should be arming and supporting al Qaeda in this effort."
- CNN's Ashley Killough contributed to this report.