Iran's supreme leader Ayatollah Ali Khamenei on Tuesday accused the United Arab Emirates of betraying the Muslim world with its agreement to normalise relations with Tehran's arch-foe Israel.
"The #UAE betrayed the world of Islam, the Arab nations, the region's countries, and #Palestine," Khamenei said, according to his official Twitter account.
"Of course, this betrayal won't last long but the stigma will stay with them," he added in a series of tweets.
In the agreement, only the third such deal it has struck with an Arab country, Israel pledged to suspend annexation of Palestinian lands.
But Prime Minister Benjamin Netanyahu stressed that did not mean Israael was abandoning plans to annex the Jordan Valley and Jewish settlements across the occupied West Bank.
"I hope the Emiratis soon wake up and compensate for what they have done," Khamenei said.
"The UAE rulers opened the door of the region to the Zionists, and they have ignored and normalised the question of Palestine."
It was Khamenei's first reaction to the agreement between the UAE and Israel that US President Donald Trump announced on August 13.
His remarks came after a US-Israeli delegation landed in Abu Dhabi on Monday on the first direct commercial flight from Tel Aviv to mark the normalisation of ties, with Saudi Arabia allowing the flight to cross its airspace.
The Iranian foreign ministry had previously denounced the deal as an act of "strategic stupidity".
The UAE downgraded its relations with Iran in January 2016 amid rising tensions between Saudi Arabia and the Islamic republic.
Tehran-Riyadh relations deteriorated further last year following a series of attacks on tankers in sensitive Gulf waters, which Washington blamed on Iran.
Tehran denied the allegation.
Saudi Arabia and Iran, the region's two leading powers, take opposing sides in the conflicts in Syria and Yemen.