DUBAI A senior British diplomat made a brief visit to Tehran on Monday for talks with officials on the strained ties between the two countries and on Iran's nuclear program, Iran's official IRNA news agency reported.
Earlier, IRNA said Tehran and London were looking to restore full diplomatic ties, all but severed after a 2011 raid on Britain's embassy in the Iranian capital.
Simon Gass is the most senior British diplomat to visit since the raid, which came after Iranian allegations that Britain had masterminded mass protests that followed then-President Mahmoud Ahmadinejad's disputed re-election in 2009. Britain has flatly denied the accusations.
"There is the likelihood of a rise in the level of diplomatic ties between Tehran and London," IRNA quoted foreign ministry official Majid Takht-Ravanchi as saying.
Gass is also London's representative in six-power nuclear talks with Tehran, and met senior members of Iran's nuclear negotiation team, IRNA said.
The former ambassador to Tehran also discussed "latest developments in the Middle East" with Deputy Foreign Minister Hossein Abdullahian before leaving Iran late on Monday.
Iranian-British relations have thawed somewhat since the election last June of moderate President Hassan Rouhani. The two countries have exchanged non-resident charge d'affaires and a British parliamentary delegation led by former foreign secretary Jack Straw visited Tehran in January.
In a statement issued in London on Monday, the Foreign Office described Gass's visit as "the next stage in the step-by-step approach to improving relations" with Tehran, following a series of trips by Charge d'Affaires Ajay Sharma.
Iran and Britain normalized relations in 1999, a decade after revolutionary leader Ayatollah Ruhollah Khomeini's fatwa that proclaimed British author Salman Rushdie should be killed for blasphemy in his novel "The Satanic Verses".
Iran and Britain have had a troubled history dating back to British oil interests in Iran and the U.S.-British role in the 1953 overthrow of democratically-elected nationalist Prime Minister Mohammad Mossadegh, which re-established the autocratic rule of pro-Western Shah Mohammed Reza Pahlavi.
The shah was toppled by the 1979 Islamic Revolution.
(Reporting by Mehrdad Balali; Editing by Andrew Roche)