Maine Democratic Senate nominee Troy Jackson on Sunday said he has no plans to apologize to his opponent, Sen. Susan Collins (R-ME), after telling the incumbent to “shut up” during a recent debate.

Speaking with CNN’s Dana Bash, Jackson was asked about an incident during the fourth and final Senate debate in Maine in which Collins referred to a protester as one of Jackson’s supporters, to which Jackson responded by telling Collins to “shut up.” Bash asked Jackson if he regretted using the phrase, and he did not mince his words.