TEHRAN — A day after two game-changing politicians signed up at the last minute as candidates for Iran’s presidential elections in June, the country’s governing establishment reacted angrily, predicting that they would not be allowed to participate or that they would definitely lose.

Esfandiar Rahim Mashaei, a protégé of President Mahmoud Ahmadinejad, and former President Ali Akbar Hashemi Rafsanjani signed up at the end of a five-day registration period on Saturday, shocking opponents who had bet on their preferred candidates’ being the only ones running in the June 14 election.

The governing establishment, a loose alliance of conservative Shiite Muslim clerics and Revolutionary Guards commanders who hold sway over the judiciary, security forces, Parliament and state news media, came out in full force on Sunday, attacking the candidates.

“Hashemi knows he is unpopular, a loser and is too old,” Mehdi Taeb, a hard-line cleric affiliated with the Revolutionary Guards, was quoted as saying of Mr. Rafsanjani by the semiofficial Fars news agency on Sunday. He added that Mr. Mashaei “only registered because he wants to sabotage the vote, or make sure there is a low turnout and possibly cause riots on the streets.”