Sen. Marco Rubio went further than he previously had Tuesday in criticizing President Donald Trump's call for China to investigate Joe Biden — though he said he still thinks the White House will not follow through on the request.

"I don't think what he said was right. I don't agree with it," the Florida Republican told CNBC's "Squawk Alley," days after he said Trump only made his remarks to "provoke" the media.

The senator later added: "It's an offhand comment and an inappropriate one but not a real proposal or a real initiative that's [being undertaken]."

A White House spokesman declined to comment on whether Trump's request was not really a serious plan.

Trump last week said Beijing "should start an investigation" into the former vice president Biden, one of his chief rivals for the presidency in 2020, and his son Hunter. The request led to new backlash on Capitol Hill after the president's push for Ukraine to probe the Bidens sparked an ongoing House impeachment inquiry.