US Vice President Kamala Harris on Sunday said her election rival Donald Trump "demeans" the office of the president with his use of coarse language, a day after the Republican insulted her using an expletive.
Speaking in an interview aired on US broadcaster MSNBC, Harris said Trump's comment was an insult to the office and degraded the United States' moral authority internationally.
"What you see in my opponent, a former president of the United States, really it demeans the office," she said, in response to a question about the comments.
Addressing a rally in the key swing state of Pennsylvania on Saturday, Trump referred to Harris as "a shit vice president," to roars of approval from his supporters.
With just over two weeks to go until Election Day, polls show Harris and Trump are locked in a neck-and-neck race for the presidency, including in the key swing states that decide US elections.
Trump has increasingly gone off-script during campaign events, using coarse and sometimes bizarre language.
During the same event in Pennsylvania on Saturday, he referred to the genitalia of a famous male golfer.
Harris told MSNBC the former president should not be allowed to lead the country again.
"Donald Trump should never again stand behind the seal of the president of the United States. He has not earned the right," she said.
Trump's comments, she added, degraded the United States' "earned and self-appointed authority" to speak on issues such as democracy and the rule of law.
The 78-year-old's campaign has been marked by the use of strong language and claims that are often divorced from reality, especially on the key election issue of immigration.
He has likened undocumented migrants to animals, threatened revenge against his perceived enemies, praised autocrats like Vladimir Putin of Russia and described the United States as a ruined nation only he can fix.