Gingrich admitted Tuesday that his campaign was in financial trouble, but told Fox News he would spend his own money "if necessary" to keep going in his campaign.

"I have no incentive to get out, because I have a set of ideas that include $2.50 per gallon gas, etc.," Gingrich said. "So I have every incentive to stay in."

Gingrich aides also said that he would scale back his campaign travel and focus spending on nontraditional media, like Internet advertising and social media.

On Wednesday, Gingrich said Romney still "has to earn" the nomination.

“Mitt Romney doesn’t have 1,144 delegates,” Gingrich said. “There is no sign yet that he is guaranteed getting 1,144. For some reason, everybody in the establishment is chanting that [Rick] Santorum and I should quit. Well, Romney has to earn this. It’s not going to be given to him. And we have every right to run.”

A Republican presidential candidate needs 1,144 delegates to secure the party's nomination.

“Until Mitt Romney has 1,144 locked down, solidly, I owe it to the people that have helped me over the past year to represent their views and their values,” Gingrich said.