Bernie Sanders boasted about his labor support in dismissing an attack from Pete Buttigieg during the Democratic debate in Las Vegas.

Buttigieg initiated the exchange by referencing the Nevada Culinary Workers Union's opposition to Sanders over his Medicare for All healthcare proposal. "You're the one who is at war with the culinary union here in Las Vegas," the former South Bend, Indiana, mayor told Sanders.

"We have more union support than you ever dreamed of," Sanders shot back.

The union's criticism prompted attacks on social media by some of Sanders's supporters against the labor group. Sanders disavowed the attacks.

"I saw some of those Tweets regarding the Culinary Workers Union," the Vermont senator said. "I have a 30-year, 100% pro-union voting record. Do you think I would support or anybody who supports me would be attacking a union leader?"