BEAUFORT, S.C. -- Republican presidential candidate Jeb Bush has now taken to mocking Florida Sen. Marco Rubio's charge that the former Florida governor has no foreign policy experience.

"Wow, coming from a guy whose office has a hard time saying actually what his accomplishments are," he said on Wednesday. "Who says that -- going to a hearing to listen to smart people talk about things instead of actually leading. That’s kind of a low blow if you think about it."

After losing to Bush in New Hampshire, Rubio has focused more on his Miami neighbor since arriving in South Carolina, charging last week that Bush has “no foreign policy experience. I thank God every day that George W. Bush was president, but Jeb has no foreign policy experience."

A super PAC backing Rubio's bid, Conservative Solutions PAC, is also airing an attack ad in South Carolina that says Bush has ideas that are "not the answer for our future."

Bush spoke just a few miles from a major Marine Corps air station, touting his eight years as head of the Florida National Guard, reminding about 250 people that he oversaw the state's response to eight hurricanes and four tropical storms in 16 months. He said that he called about 150 families who lost loved ones during the wars in Iraq and Afghanistan. "Not an easy thing to do," he said.

"We made sure that every one of those families was taken care of. I know what it is to be commander-in-chief. I know what it is to lead," he said.

“And for someone who has no experience at all to suggest I don’t -- having lived overseas, having worked overseas, developing relationships with leaders overseas, being governor of the fourth largest state and being a commander-in-chief of the Florida National guard. With all due respect Senator Rubio, your four years or five years or whatever it is as senator does not match up to my capabilities of understanding how the world works.”

As Florida governor, Bush led 15 trade missions to Mexico, Israel, Canada and Europe. He's made 89 foreign trips to six continents since leaving office in 2007, according to aides.

Rubio's attacks clearly sting Bush and come as recent polling here gives the senator a slight edge, although some surveys put the two Floridians in a statistical tie for second or third place in Saturday's GOP primary.

Campaigning in this tiny southern hamlet, Bush was introduced by former Navy admiral Bob Natter, who once served as commander of the U.S. Atlantic Fleet, and Doug Burnett, the former adjutant of the Florida National Guard, both of whom talked up Bush's leadership of Florida during the storms and what they think is a deep understanding and appreciation for the military.

Bush has two other stops scheduled across the Palmetto state on Wednesday. On Friday, he is scheduled to campaign with his mother, former first lady Barbara Bush, in northern parts of the state.