Israeli Prime Minister Benjamin Netanyahu on Saturday dismissed the significance of reports that the new Iranian president and his foreign minister had both issued greetings to mark the Jewish New Year.
Twitter messages that appeared to have been issued by newly-elected Hassan Rouhani and Foreign Minister Javad Zarif, wishing Jews a good Rosh Hashanah - the Jewish New Year, which was celebrated this week - made headlines in Israel.
They were a change in tone from Rouhani's predecessor, Mahmoud Ahmadinejad, who left office last month and regularly use to rile Israel by calling for the destruction of the "Zionist entity".
Netanyahu said in a statement he was "not impressed", and that the Iranian regime "will be judged only by its actions and not by greetings" whose purpose, he said, was to deflect attention from its nuclear programme.
He called on the international community to strengthen sanctions on Iran meant to curb its nuclear activities.
Relations between the two countries have been dire for decades. Israel says all its options are on the table in preventing Iran from developing nuclear weapons that could one day jeopardize the survival of the Jewish state.
Iran denies it wants nuclear weapons and says its nuclear programme is for civilian purposes.
Rouhani's election in June has encouraged speculation that Tehran may be taking a more conciliatory approach to foreign affairs, though the president's power is heavily circumscribed by the clerical hierarchy.