Twitter is blowing up with the announcement that Rick Santorum is suspending his campaign for the GOP nomination. From CNN:

Santorum spoke to GOP presidential front-runner Mitt Romney prior to his expected announcement, according to another source close to the campaign.

An additional source told CNN that Santorum, his wife, and campaign manager held a conference call with staff Tuesday, advising them not to grow discouraged.

"We are going to stay involved and stay active in the next couple of months," Santorum said, according to the source.

Santorum is currently answering questions from reporters. You can watch it here.