Backlash from President Hassan Rouhani's visit to the UN, which included a conversation with President Barack Obama, has taken a public turn with outdoor posters

Tehran's streets are dotted with billboards questioning the United States's honesty in its direct talks with the Iranian government.

Tehrani citizens have in recent days noticed billboards showing an Iranian negotiator talking face to face to his American counterpart behind a table. The US negotiator is half-civilian, half-military with a pump-action shotgun on his lap. "The US government styles honesty," reads the billboard.

Hassan Rouhani's administration has come under attack by hawks and hardliners at home since the new Iranian president spoke to Barack Obama during his UN visit in New York, which marked the first direct talks between US and Iranian presidents since the 1979 Islamic revolution.

Mohammad Javad Zarif, Iran's foreign minister, and John Kerry, the US secretary of state, also spoke during the highest-level meeting between Tehran and Washington in more than three decades on the sidelines of negotiators over the Iranian nuclear programme at the UN.

But Rouhani's extraordinary UN visit is still creating ripples in Tehran with some hardliners saying he went too far by speaking to Obama. General Mohammad Ali Jafari, commander of the Islamic republic's revolutionary guards, also labelled the phone conversation as premature.

Billboards destined for public places in Iran must be vetted by the authorities, meaning that their distribution around Tehran has had some sort of official backing. It is not clear which political groups are behind the billboards but they have been designed by the Islamic Republic Designing House, which has pictures posted on its website showing the billboards across the city.

Teribon, the conservative Iranian news website conducted an interview with designers. Teribon said the billboards were "a spontaneous reaction" to the nature of holding talks with the United States.

"We believe that art has more influence in introducing and showing the essence of our enemies, more than political statement," one of the organisers behind the "US honesty" project told Teribon.

"Some experts believe that Obama has no authority in regards to Iran and it's the Israeli lobby in America which has the first and final word," Teribon said.

There are a large number of Iranian politicians and activists who have endorsed Rouhani's bid to improve relations with the west, especially the United States. In response to criticism, Rouhani has pledged to conduct national polls to gauge Iranians' support for direct talks with the US.

Meanwhile, a group of Iranian hardliners have set up a seminar for next month called "the great conference of Down with America". Organisers have also planned "the first major international award of Down with America", asking people to send their work for a prize judged by three men. The winner is promised a $4000 prize.