The Tehran municipality has removed anti-American posters from the streets of the capital which questioned US honesty in nuclear talks with Iran, media reported on Sunday.
The move comes as President Hassan Rouhani, a reputed moderate, has made fresh overtures to the West, including direct talks between US and Iranian officials, and ahead of the 34th anniversary of the US embassy seizure in Tehran.
A municipal spokesman said the posters were put up across Tehran without any official authorisation.
"In an arbitrary act and without the knowledge and confirmation of the municipality, one of the advertising agencies had put up these posters," spokesman Hadi Ayyazi was quoted as saying by the official IRNA news agency.
AFP photographers said that some posters could still be seen across Tehran.
One of them, bearing the words "American honesty," shows US and Iranian negotiators sitting at a table and facing each other, the American wearing a jacket and tie but with army pants and boots underneath.
Ehsan Mohammad-Hassani, head of the Oj adverting agency, which produced the posters, told the Fars news agency they did not reflect hostility towards US-Iranian nuclear talks.
"The American Honesty posters do not have any objection against Iran-America negotiations," he was quoted as saying.
Rouhani, a moderate cleric who has pledged to improve ties with the West, held a historic 15-minute telephone conversation with US President Barack Obama last month, the first direct contact between leaders of the two countries in more than three decades.
The call came as Rouhani was winding up a visit to New York where he attended the UN General Assembly.
Supreme leader Ayatollah Ali Khamenei has backed Rouhani's overtures but criticised some aspects of the UN visit as "inappropriate."
Iranians are also split over whether it is still appropriate to chant "Death to America" -- one of the main slogans of the 1979 revolution -- at official ceremonies.
4 November is the anniversary of the seizure of the US embassy in Tehran, during which Islamist students captured and held 52 US diplomats hostage for 444 days.
The crisis triggered the severance of all diplomatic relations between the two countries and contributed to decades of mutual hostility.
Iran and so-called P5+1 -- the United States, France, Britain, Russia, China and Germany-- resumed nuclear talks in mid-October and will meet again on November 7 and 8 in Geneva to try and resolve the dispute over Iran's nuclear programme.
Israel and the West have long accused Tehran of pursuing a nuclear weapon in the guise of a civilian programme, charges adamantly denied by Iran, which insists its nuclear programme is entirely peaceful.