Qatar's decision to return its ambassador to Tehran "embarrasses Doha and reveals its political tactics", the UAE Minister of State for Foreign Affairs Dr Anwar Gargash said on Friday.
In a series of tweets, Dr Gargash also questioned the reasoning behind the move, which comes at a time when the UAE, Saudi Arabia, Bahrain and Egypt are boycotting Qatar over its closeness to Iran and its support for individuals and groups linked to extremism and terrorism.
He said Qatar’s decision to restore full diplomatic relations with Iran was accompanied by a “confused justification”.
Qatar’s "soverign decision should not be shy or confused, but it’s arrogance and adolescent behaviour makes it so”, he tweeted. "It's justification is not convincing."
Dr Gargash said the reference to the UAE’s trade relations with Iran to “justify the return of the Qatari ambassador disregards Iran's main interest in the Gulf which lies in Qatar’s gas fields”.
Qatar’s announced that its ambassador to Tehran would "return to resume his diplomatic duties" on its foreign ministry website on Thursday.
The Qatari decision was conveyed by foreign minister Sheikh Mohammed bin Abdulrahman Al Thani during a phone call with his Iranian counterpart Mohammad Javad Zarif to discuss "bilateral relations and means of boosting and developing them", Iranian foreign ministry spokesman Bahram Qassemi said.
"We welcome this measure by the Qatari government," Mr Qassemi said, according to the state-run IRNA news agency.
Qatar had withdrawn its ambassador early last year in a show of solidarity with Saudi Arabia, after two Saudi diplomatic posts in Iran were attacked during protests against the kingdom's execution of a prominent Shiite cleric.
However, the two countries maintained commercial ties, particularly their joint operation of the world's largest gas field, called the South Pars Field by Iran and the North Field by Qatar.
Since the diplomatic dispute with the quartet of Arab nations began in June, Iran has allowed Qatar's national carrier to use its airspace and sent fresh food supplies to Doha.