The GOP's two presidential rivals from Florida -- Jeb Bush and Marco Rubio -- both speak fluent Spanish and are believed to have the best chances within their party to score points with the key Latino demographic.

But the former governor and current senator have long left behind their mentor-protégé relationship and are increasingly going after one another, the Associated Press reported.

Rubio, the 44-year-old son of two Cuban immigrants, said that the 2016 election marks "a generational choice" and has subtly attacked Bush, the brother of former President George W. Bush and son of former President George H.W. Bush, as a "legacy" candidate akin to Democratic frontrunner Hillary Clinton, the newswire noted.

"We will not change direction if all we do is keep electing the same kind of people," the senator recently told a crowd at an event in the key early-primary state of New Hampshire. "This election cannot be one of those elections where we just promote the next person in line, where we just vote for the person the experts tell us we have to vote for."

Bush, meanwhile, has been outspoken in his criticism of his former mentee, going so far as to rip Rubio's attendance in the Senate, according to ABC News.

"As a Floridian, I'm a little disappointed, because he's missing, like, 35 percent of his votes," Bush said of Rubio as he spoke to group of College Republicans in New York last week. "And it's just, kind of, like, dude, you know, either drop out or do something. But we're paying you to do something; it ain't run for president."

Rubio, for his part, has been a bit more reserved when it comes to picking an open fight with his GOP rival, the network noted.

"When candidates are running, I think they're going to say things that they think will make them stronger in the race," he said. "I have great admiration and respect for (Bush) as a person; I'm not running against Jeb Bush. I'm running for president."