Donald Trump: Rick Santorum Should 'Bow Out With Dignity'

Business mogul Donald Trump is calling for Rick Santorum to leave the race for president.

"This is a great time for @RickSantorum to bow out with dignity," Trump tweeted Thursday morning.

Trump, who endorsed Mitt Romney in February, previously slammed Santorum for his loss in the 2006 Senate race and criticized him for continuing to campaign.

"He's not going to win ... it's just not going to happen," Trump told Fox News in March. "At a certain point you have to get behind a person and you have to start going after Obama, not each other. And what Republicans are doing is disgraceful."

Trump has had his own moments in the sun during the 2012 election, including hinting that he might run for president and unsuccessfully attempting to organize a presidential debate.