Vice President Kamala Harris, who is running for the post of US president from the Democratic Party, has suggested that her Republican Party rival and former President Donald Trump take a cognitive ability test. She announced this in an interview with CBS, the latter reports.

Harris's comments referred to the statements of Trump, who has repeatedly made insulting statements about the vice president's intelligence.

Specifically, Harris said she would take a cognitive test and "would challenge him to take the same one."

"I think he actually is increasingly unstable and unhinged and has resorted to name calling because he actually has no plan for the American people," Harris said of Trump.

The US vice president pointed to a number of people who have worked closely with Trump but have come out against him in recent weeks. Harris considered this proof that Trump is "unfit to be president of the United States."