Trump goes after Sanders' taxes, Fox News appearance Sanders, in response, said Trump was scared of his campaign.

President Donald Trump, in a trio of tweets Tuesday evening, targeted Sen. Bernie Sanders’ presidential prospects, tax returns and his Fox News appearance the day before.

The Vermont senator released 10 years of his tax returns Monday and called on Trump to do the same during a Fox News town hall in Bethlehem, Pennsylvania.

“Hey, President Trump, my wife and I just released 10 years. Please do the same. Let the American people know," Sanders said.

Seemingly in response, Trump tweeted that Sanders “made a fortune off of Trump” and that he and his wife “should pay the Pre-Trump Taxes on their almost $600,000 in income.”

The documents Sanders released on Monday show he earned an adjusted gross income of nearly $561,293 and paid $145,840 in taxes, an effective rate of 26 percent.

Trump also appeared to criticize Fox News, claiming the network did not allow his supporters to attend the town hall with Sanders.

But the regional paper that covers Bethlehem, The Morning Call, interviewed two Trump supporters who were in the audience at the event. And Fox News anchor Martha MacCallum, who hosted the town hall with fellow anchor Bret Baier, told the paper that “Fox reached out to various political and local groups in the area and mined requests to attend after it publicly announced the event.”

Trump also offered his predictions on who might be the 2020 Democratic presidential nominee, saying he looks forward to facing either Sanders or former Vice President Joe Biden in the general election. Biden has yet to announce whether he is running for President.

Sanders’ camp, responding to Trump, tweeted, “Looks like President Trump is scared of our campaign. He should be.”

ABC News' Cheyenne Haslett, Adam Kelsey and Lissette Rodriguez contributed to this report.