Iran's supreme leader has called the United Arab Emirates' recognition of Israel "treason that will not last for long", the state media in Iran reported on Tuesday.
The comments by Ayatollah Ali Khamenei come just as a joint US-Israeli delegation wrapped up a trip to Abu Dhabi on the first Israeli commercial air flight between the nations.
Khamenei said the "treachery" was committed against the entire Islamic world and the Palestinians.
Both Israel and the UAE view Iran with suspicion.
"The UAE betrayed the Islamic world, Arab nations and the regional countries, as well as the cause of Palestine," Xinhua news agency quoted Khamenei as saying.
"They (the UAE officials) opened the region to the Zionists (Israelis) and put the cause of Palestine, which is a usurpation of a country, into oblivion," he said.
Iran has strongly condemned the August 13 agreement, brokered by the US, between Israel and the UAE to work towards a "full normalization of relations".
As part of the deal, Israel will suspend the annexation of Palestinian lands in the occupied West Bank, while it focuses on expanding ties with other Arab countries with other nations in the Muslim world.