"Right now we're facing an emergency goal of $100,000 to help get our ads on the air. We need your contribution by 11:59 P.M. Tonight," the email read.
The campaign email took aim at presumptive Democratic presidential nominee Hillary Clinton's recent general election ads and, again, called her "Crooked." It added that the donations were needed by midnight on Saturday in order to get Trump's ads on-air.
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"Crooked Hillary is about to invade your TV with ads attacking Trump. But we're preparing to fight back."
The urgent call for donations came on the same day that Trump said he would fund his own campaign if needed. During a rally in Las Vegas Saturday, the billionaire businessman threatened to self-fund his general election efforts if GOP leaders' support begins to waver.
The money plea comes as Trump's poll numbers have taken a massive nosedive. The presumptive Republican nominee's average polling rating against Hillary Clinton has dropped by double digits in the last month.
The dip came a day after a poll suggested the GOP may be in trouble too. A Bloomberg poll released Wednesday, found just 32 percent of Americans viewed the Republican Party favorably. It's the lowest that rating the GOP has received since the poll's inception in 2009.
The Democratic Party was viewed much higher, with 49 percent favorability.