Former Secretary of State John Kerry blasted President Trump for his attacks on former Vice President Joe Biden Sunday, calling Trump’s words “unbecoming of a president” and asking why the president isn’t more focused on his job.

"It's so personal. So unbecoming of a president of the United States to engage in that ... it shows fear or something, I don't know," Kerry told CBS' "Face the Nation." "Why is he picking that at this point in time when he has major issues he needs to deal with?"

Kerry's remarks came days after Trump called Biden a “dream” opponent in the 2020 presidential election and were part of a harsh critique of the president that suggested Trump was creating a diversion to the issues facing his White House.

"Look, Joe Biden ran [for president] three times," Trump told CBS News last week. "He never got more than one percent and President Obama took him out of the garbage heap, and everybody was shocked that he did. I'd love to have it be Biden."

Biden, who is widely considered the current frontrunner to win the Democratic nomination in 2020, has recently stepped up his criticism of Trump.

Speaking recently on a podcast called "Anger Management," Biden said that Trump’s "zero tolerance" immigration policy made him “feel ashamed” and added that U.S. credibility on the world stage was deteriorating.

“The reason why the rest of the world in large part has repaired to us is not the example of our power, but the power of our example,” Biden said.

He added: “And we are sending a signal that I just think is so, so damaging to our ability to be a positive force in being among the leaders in the world. Whether it’s that, or whether it’s praising [Philippines leader Rodrigo] Duterte or praising {Vladimir] Putin or praising Kim Jong Un. I mean, what are we doing?”

Kerry’s comments come after a difficult week for Trump, who took a bipartisan beating for his contradictory statements about Russia's culpability for interference in the 2016 presidential election and for raising doubts about the U.S. intelligence community's conclusions about Moscow’s meddling.

"That's what he's trying to run away from," Kerry said. "He 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," Kerry said, adding "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."