WASHINGTON – Anthony Scaramucci is upping the ante in his rhetorical war with President Donald Trump, saying Republicans should think about replacing the president as their nominee in the 2020 election.

"You are losing your fastball," Scaramucci tweeted Monday, responding to Trump's latest volley of criticism, later adding: "Time to call in a good relief pitcher."

The former White House communications director – he served only 11 days back in 2017 – also told Trump that "bullying is the most anti-American thing in our culture and it is emanating from the Oval Office," and claimed that "many have called and are willing to work on a necessary replacement."

Trump had tweeted just minutes earlier that Scaramucci – "who like so many others had nothing to do with my Election victory" – is upset only because "I didn’t want him back in the Administration (where he desperately wanted to be)." Trump also said he rarely returned Scaramucci's calls, and that his former supporter "just wanted to be on TV!"

The latest round in Trump-vs.-Scaramucci began earlier Monday, when Scaramucci told CNN that he no longer supports Trump, citing his recent comments about minority lawmakers and the way he has handled himself after the mass shootings in El Paso, Texas, and Dayton, Ohio.

"I'm a Republican, so I'm not switching parties to support a Democrat," Scaracmucci said on CNN's New Day. "But I'm now neutral on the president ... He's sounding more and more nonsensical." On Sunday, Scaramucci told the website Axios: "A couple more weeks like this and 'country over party' is going to require the Republicans to replace the top of the ticket in 2020."

In a string of recent interviews, Scaramucci has hit Trump for talking more about himself and his campaign during last week's visits to El Paso and Dayton to meet with survivors of the mass shootings.

A “total disaster," Scaramucci said on CNN, and "one of the worst weeks of his presidency."

Trump feuded over the weekend with Scaramucci, bashing him as an attention-seeker who only wants to go on television to talk about him.

"Anthony Scaramucci, who was quickly terminated (11 days) from a position that he was totally incapable of handling, now seems to do nothing but television as the all time expert on 'President Trump'," Trump said on Twitter. "Like many other so-called television experts, he knows very little about me."

Scaramucci responded on Twitter by noting that Trump turns against everybody.

"For the last 3 years I have fully supported this President," Scaramucci wrote. "Recently he has said things that divide the country in a way that is unacceptable. So I didn’t pass the 100% litmus test."

He added: "Eventually he turns on everyone and soon it will be you and then the entire country."