Kentucky senator and GOP presidential candidate Rand Paul tells Newsmax TV he would like to find out how Islamic State (ISIS) militants are getting American weapons.

"Most of these people do not have the sophistication to make arms so they get the arms from other folks," he told "The Hard Line" host Ed Berliner.

"Right now ISIS has a billion dollars' worth of U.S. Humvees, they have a billion dollars in cash they stole from us and they pay their soldiers with but they have anti-tank weapons and missiles they fire from the shoulder that were basically given to people in the Syrian civil war and taken by ISIS."

During the Libyan civil war, 15,000 shoulder-to-air missiles made by the United States disappeared, he added. "That's why there is a concern that airliners might be taken down by shoulder-to-air missiles. … That might be a good reason for why we should've thought long and hard before we agreed with Hillary Clinton and Barack Obama to get involved in a war in Libya."

Paul said he believes the CIA's presence in Libya had something to do either with getting shoulder-fired missiles to Syrian rebels or someone else and out of the hands of terrorists.

Paul said he wants to do everything possible to keep Americans safe, but said he doesn't think that includes the current policy of siding with al-Qaida-linked rebels in Syria against President Bashar Assad. Taking out Assad will only create a vacuum like the United States did in Iraq when it removed Saddam Husseing from power, he said.