Marco Rubio on Friday said the Republican Party would split apart if Donald Trump becomes the 2016 GOP presidential nominee.
Speaking to reporters in Oklahoma City, Rubio was asked if he would support Trump if he wins his party's nomination.
"He's not going to be the nominee," Rubio shot back. "The Republican Party would be split apart if he's the nominee."
Rubio called Trump the current front-runner, but vowed to stop him.
"He could become the nominee and we're not going to let that happen. There is no way we're going to allow the party of Reagan or the conservative movement to be taken over by a con man," he said.
Trump has "conned a significant number of Americans into believing something he's not," Rubio said. Rubio pointed to remarks in Thursday night's debate in which Trump defended the services provided by Planned Parenthood to women suffering from different types of cancer, and stated that he would remain neutral in negotiations between the Israelis and Palestinians.
Rubio said those positions would mark a "stunning shift for this party."
"He's a con man. I think it's time to unmask him for what he is. He's trying to take over the conservative movement," he said.
Rubio's remarks came just a short while after New Jersey Gov. Chris Christie's surprising endorsement of Trump at a press conference in Fort Worth, Texas, and the day after Rubio aggressively went after Trump at Thursday night's Republican presidential debate.
The remaining five Republican candidates will face off on Super Tuesday next week when 13 states hold primaries or caucuses.