"I don't respond to Bernie's ridiculous comments," Biden told the press Friday. He was responding to a question about Sanders questioning the former Delaware senator's judgement on the Iraq War.
When a reporter asked if Biden had any concerns about Sanders' own thoughts on foreign policy, he again avoided direct comment.
“You’re not going to get me in a fight with Bernie. Bernie's got enough baggage," Biden said.
Their comments came as Democrats came closer to the Iowa caucuses in February. National polling has typically shown Biden as the frontrunner with Sanders coming in second or third.
According to RealClearPolitics' polling average, Biden maintained a 10 point lead over Sanders (29.4 percent versus 19.4 percent).
In an interview with The Washington Post published Thursday, Sanders appealed to primary voters to look past Biden's "perceived electability" and instead focus on voters' "appetite for sweeping change."
“It’s just a lot of baggage that Joe takes into a campaign, which isn’t going to create energy and excitement,” Sanders told The Post. “He brings into this campaign a record which is so weak that it just cannot create the kind of excitement and energy that is going to be needed to defeat Donald Trump.”
Fox News' Joseph A. Wulfsohn contributed to this report.