Iranian Foreign Minister Ali Akbar Salehi held talks on Monday with top Emirati officials on a surprise visit to the United Arab Emirates, the state news agency WAM reported.
Salehi "discussed ways of enhancing bilateral relations" and "matters of bilateral interest" with Deputy Prime Minister Sheikh Mansur bin Zayed al-Nahayan, who also holds the presidential affairs portfolio, WAM said.
Salehi's surprise visit comes amid tense relations between Iran and the UAE over three disputed islands in the Gulf -- Abu Musa, the Greater Tunb and the Lesser Tunb, with each country claiming ownership of the islands.
Iranian President Mahmoud Ahmadinejad triggered the fury of the UAE when he visited Abu Musa, the largest of the three islands, in April to reinforce the Tehran's claim. The head of Iran's powerful Revolutionary Guards visited them in May.
The UAE claims ownership over the islands in line with a 1971 agreement signed when Britain ended its colonial-era reign over that part of the Gulf. But Iran insists the islands have always been part of its territory.
The islands are strategically located in the oil-rich Gulf, permitting control over access to the waterway and Iran maintains a military base and airfield on Abu Musa.
In June the United States backed the UAE's claim of ownership prompting anger in Tehran which accused Washington of interfering in Iranian domestic affairs.
Iran's Arabic-language television Al-Alam, meanwhile, reported that Annan had arrived Monday in Tehran from Syria for talks with the Islamic republic's top security official and foreign minister.
Annan has maintained that Iran has a key role to play in efforts to end the nearly 16-month-old deadly conflict in Syria. He also visited Tehran on April 10.
Before leaving Damascus, Annan said he had agreed with President Bashar al-Assad on a new political "approach" to end the crisis in Syria, and that he would put this to the rebels.
The UAE has condemned the deadly crackdown on dissent in Syria, recalling its ambassador from Damascus and expelling Syrian envoys along with its other five partners in the Gulf Cooperation Council.