Austin, Texas (CNN) Rep. Tulsi Gabbard, a Democratic presidential candidate, would not say Sunday whether she believes Syrian dictator Bashar al-Assad is a war criminal.

"I think that the evidence needs to be gathered and, as I have said before, if there is evidence that he has committed war crimes, he should be prosecuted as such," Gabbard said at a CNN town hall Sunday.

Gabbard met with Assad in Syria two years ago, saying at the time that she "felt that it's important that if we profess to truly care about the Syrian people, about their suffering, then we've got to be able to meet with anyone that we need to if there is a possibility that we can achieve peace."

Gabbard also said last month that Assad is "not the enemy of the United States because Syria does not pose a direct threat to the United States."

When moderator Dana Bash asked if Gabbard is unsure whether Assad is a war criminal now, she said: "Everything that I have said requires that we take action based on evidence. (If) the evidence is there, there should be accountability."

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