JERUSALEM — Prime Minister Benjamin Netanyahu of Israel said in a statement on Saturday night that he was “unimpressed” by reports that Iran’s new president, Hassan Rouhani, issued greetings for the Jewish New Year last week on Twitter.

“The Iranian regime will be judged only by its actions and not by its greetings,” Mr. Netanyahu said. He added that the greetings’ “only purpose is to distract attention from the fact” that despite the election of Mr. Rouhani, considered a moderate, “it continues to enrich uranium and build a plutonium reactor for the purpose of developing nuclear weapons that will threaten the state of Israel and the entire world.”

On Wednesday, a message was posted on a Twitter account attributed to Mr. Rouhani saying, “As the sun is about to set here in #Tehran I wish all Jews, especially Iranian Jews, a blessed Rosh Hashanah.” A presidential adviser later told the Iranian Fars News Agency that the president does not have a Twitter account.

On Thursday, a Twitter account attributed to Iran’s foreign minister, Mohammad Javad Zarif, posted “Happy Rosh Hashanah,” the Hebrew name for the New Year’s holiday celebrated from Wednesday evening through Friday evening. Mr. Zarif later confirmed to CNN that he had sent New Year’s greetings.