Sen. Bernie Sanders’ (I-VT) has offered an apology to former female staffers from his 2016 presidential campaign who have complained of sexual harassment but maintained that he was not aware of the allegations at the time. Asked to respond to a New York Times article detailing allegations of sexual harassment, gender disparity, and unequal pay, Sanders told CNN’s Anderson Cooper late Wednesday that he’d “do better” next time if he runs again. While he said he was “proud” of his campaign, Sanders acknowledged that allegations of mistreatment were “not dealt with as effectively as possible.” But he said he had only recently learned of the allegations and was not made aware of them during the campaign. “I was a little busy running around the country, trying to make the case” for the election, he said. “I certainly apologize to any woman who felt that she was not treated appropriately, and of course, if I run, we will do better next time,” he said. Several former staffers had told the New York Times in a story published Wednesday that they experienced mistreatment or sexual harassment during Sanders’ campaign—and that there were no means of recourse for them to seek help. Female staffers also alleged that they were paid substantially less than their male counterparts or subordinates. One woman told the Times she made $2,400 a month—but that a younger man who was supposed to work under her made $5,000.