Former Secretary of State John Kerry said President Trump's derisive comments about former Vice President Joe Biden "show fear" and that the president lobs such provocative remarks as a "diversion" to pivot from important topics like Russia.

Kerry made the comments in an interview with "Face the Nation" after what he described as Mr. Trump's "disgraceful" and "dangerous" press conference with Russian President Vladimir Putin in Helsinki, Finland, on Monday. Mr. Trump has extended an invitation to Putin to meet again in Washington this fall.

In an interview with "CBS Evening News" anchor Jeff Glor earlier this week, Mr. Trump said former President Barack Obama took Biden out of the "garbage heap," and said he dreams of running against Biden in 2020. Kerry called the comments "outrageous" and "so personal," but said the president wants to focus on things like trashing Biden "because he doesn't know how to do the real business of our country."

When "Face the Nation" moderator Margaret Brennan asked Kerry to respond to Mr. Trump's derision of Biden, Kerry responded, "Well, basically I'd prefer not to, to be honest with you."

"I think it's so outrageous," Kerry said. "It's so personal. So unbecoming of a president of the United States to engage in that kind of -- it shows fears. I don't know. Why is he picking that at this point at this point in time when he has major issues he needs to deal with?"

"Here's the bottom line," Kerry continued. "President Trump went over to have a much-heralded summit with President Putin. When he came out after two hours alone with President Putin, did they announce anything? Did they say they have an approach they are commonly going to work on towards Syria? Did they say that they were going to do something about the middle east and violence? Did they say they had a common approach to counterterrorism? Did they say they're going to deal with North Korea? Any other of a number of major international issues. No! Nothing! Not one single positive agenda, agreement for moving forward. That's what he's trying to run away from."

Kerry said Mr. Trump "wants to have you raising the question you just raised with me, which is the real question in the moment, nothing about Joe Biden or what happened in the last campaign and everything. What he does is, he's always looking for the diversion, always moving away from the real business of our country because he doesn't know how to do the real business of our country."

Kerry also declared Mr. Trump's press conference with Putin to be "one of the most disgraceful, remarkable moments of kowtowing to a foreign leader by an American president that anyone has ever witnessed."

"It wasn't just that it was a kind of surrender. This is dangerous. The president stood there and did not defend our country. He stood there and did not defend the truth," he said.