Donald Trump speaks while campaigning at the Hagerstown airport April 24, in Hagerstown, Maryland. | Getty Trump to Clinton: 'Time to get it on!'

Now more than ever, Donald Trump is apparently girding for a general-election rumble with Hillary Clinton.

"I look so forward to debating Crooked Hillary Clinton!" Trump tweeted Tuesday night, after The Associated Press declared the Kentucky primary between Clinton and Bernie Sanders too close to call. "Democrat Primaries are rigged, e-mail investigation is rigged - so time to get it on!"

Advertisement I look so forward to debating Crooked Hillary Clinton! Democrat Primaries are rigged, e-mail investigation is rigged - so time to get it on! — Donald J. Trump (@realDonaldTrump) May 18, 2016

Trump tweeted earlier in the evening that Clinton should drop out of the Democratic race if she cannot close the deal in Kentucky.

"Do you think Crooked Hillary will finally close the deal? If she can't win Kentucky, she should drop out of race. System rigged!" he wrote.