Washington (CNN) - Ben Carson says he wouldn't use drones to kill undocumented immigrants -- but he'd order strikes on the caves used to transport people across the United States' southern border.
He added emphatically: "I'm not talking about killing people. No people with drones."
Carson, a retired neurosurgeon who is now among the top polling candidates for the Republican presidential nomination, also proposed using military strategists and the National Guard to secure the border.
He suggested last week that he would consider using drones along the border -- but said Sunday that he only meant they could be used to watch porous portions of the border, and to shut down "the caves that are utilized to hide people" by smugglers.
Following a well-received performance at the first GOP debate and his frequent criticism of Planned Parenthood, Carson has recently seen interest in his campaign rise. In Tuesday's CNN/ORC national poll, Carson placed third after Trump and former Florida Gov. Jeb Bush.
Carson, a retired neurosurgeon who rose to political prominence two years ago with his blistering attack against President Barack Obama's policies at the National Prayer Breakfast, has rallied much of the GOP's conservative Christian base with a cry for greater religious freedoms and his fierce opposition to abortion rights.
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Carson says he opposes abortion today, despite a history as "a pretty left-wing Democrat" who once disavowed a television ad he appeared in promoting an anti-abortion ballot measure in Maryland.
Carson said he changed his mind on abortion after thinking through how slavery was eliminated.
In 1992, Carson appeared in a video that urged voters to reject a controversial Maryland referendum that sought to make it easier for women to get an abortion. The video, sponsored by anti-abortion group Vote Know, made clear in a tagline at the end that it was urging voters to vote down the measure.
Soon after, Carson appeared in a press conference in which he backed away from taking a stance on the issue. He said he did not realize the ad would take a political position on the referendum.
But the media avail was sponsored by Maryland for Choice -- a pro-abortion rights organization.
Anti-abortion activists said at the time that political pressure may have caused Carson to back away from his support for their cause.
Abortion rights activists, however, praised Carson's decision to denounce his appearance in the anti-abortion ad.
Carson's message has resonated with Republican voters. In a CNN/ORC poll earlier this month, he tied with former Arkansas Gov. Mike Huckabee as the best GOP candidate to handle abortion, grabbing 17% of the vote. And he was the considered the top GOP candidate who "best represents Republican values."
CNN's Ashley Killough contributed to this report.