Vivek Ramaswamy, Chris Christie come to blows in one of the most contentious debate battles yet

Chris Christie and Vivek Ramaswamy went after each other during the fourth Republican presidential debates in one of the most heated fights yet.

Former New Jersey Gov. Chris Christie and businessman Vivek Ramaswamy went after each other Wednesday in one of the most contentious fights yet at one of the Republican presidential primary debates.

The fight broke out after Ramaswamy mocked former South Carolina Gov. Nikki Haley's intelligence, saying both she and President Joe Biden couldn't name "three provinces in eastern Ukraine that they want to send our troops to actually fight for."

"She has no idea what the hell the names of those provinces are, but she wants to send our sons and daughters in our trimmings and our military equipment to go fight it," said Ramaswamy, who has criticized Haley's foreign policy views as too hawkish.

"Look at the blank expression," he added. "She doesn’t know the names of the provinces."

Before Haley, a former U.S. ambassador to the United Nations, could respond to Ramaswamy's missive, Christie took aim at him, first blasting him as a flip-flopper who backs away from certain comments he has made previously on the campaign trail.