DENVER -- The war of words between Rep. Tom Tancredo, R-Colo., and Florida's Gov. Jeb Bush is heating up.

After Tancredo called Miami a "third world country," over the weekend, Bush defended his state calling Tancredo's initial remarks "politically correct happy talk."

Tancredo fired back with a letter that said Bush is naive to ignore the problems of overwhelming immigration.

"I certainly understand and appreciate your need and desire to create the illusion of Miami as a multiethnic 'All American' city," Tancredo said. "I can also appreciate that Miami's schools graduate many outstanding students and that the cultural and ethnic diversity of the city offers many advantages to its residents," Tancredo wrote to Bush.

"However, it is neither naive nor insulting to call attention to a real problem that cannot be easily dismissed through politically correct happy talk," his letter continued.

Then on Wednesday, Bush -- the President's younger brother -- called Tancredo a "nut."

Talking with reporters, Bush said Miami is just as American as suburban Denver.

Both Bush and Tancredo are Republicans. But Tancredo, who represents the Sixth District, south of Denver, has repeatedly argued for tougher immigration laws.