Democratic presidential candidate Bernie Sanders criticized rival Hillary Clinton during last night's Democratic debate over her relationship with Henry Kissinger, whom the Vermont senator called "one of the most destructive secretaries of state."

"In her book and in this last debate, she talked about getting the approval or the support or the mentoring of Henry Kissinger," said Sanders, reported ABC News. "Now I find it rather amazing because I happen to believe that Henry Kissinger was one of the most destructive secretaries of state in the modern history of this country." He added: "I'm proud to say that Henry Kissinger is not my friend. I will not take advice from Henry Kissinger."

Clinton attempted to hit back at Sanders for his lack of foreign policy advisers, saying, "Well, I know journalists have asked who you do listen to on foreign policy and we have yet to know who that is."

Sanders shot back: "Well, it ain't Henry Kissinger, that's for sure."

Kissinger, who is now 92, served under Presidents Richard Nixon and Gerald Ford and has remained active in foreign policy circles. In 1973, he received the Nobel Peace Prize, but Sanders was critical of Kissinger for "destabilizing the political situation in Southeast Asian countries and paving the way for the Khmer Rouge's mass killing of three million people in Cambodia," according to CBS News. Sanders called it "one of the worst genocides in the history of the world," and said, "So, count me in as somebody who will not be listening to Henry Kissinger."

Clinton sought to defend Kissinger by saying he paved the way for better relations with China.

"You know, I listen to a wide variety of voices that have expertise in various areas," said Clinton, according to the Washington Post. "I think it is fair to say whatever the complaints you want to make about him are, that with respect to China - one of the most challenging relationships we have - his opening up China and his ongoing relationships with the leaders of China is an incredibly useful relationship."