The Iranian charm offensive that began with the election of Hassan Rouhani as president three months ago took a bizarre twist last week with a series of Rosh Hashanah greetings tweeted by the new president and his foreign minister. Meanwhile, diplomats are preparing new rounds of nuclear talks.

The greetings began on Wednesday with a tweet in English from an account that appeared to belong to Mr Rouhani. “As the sun is about to set here in #Tehran I wish all Jews, especially Iranian Jews, a blessed Rosh Hashanah,” it said, along with a photograph of a Jewish man praying.

The tweet caused a flurry of excited reports but was later disowned by the president’s office, which said that Mr Rouhani did not have a Twitter account. Later, however, sources in Tehran said that it was “semi-official” and maintained by the president’s aides.

In another tweet — which was not denied — the new Foreign Minister, Javad Zarif, sent out the simple message: “Happy Rosh Hashanah.” Christine Pelosi, daughter of the former speaker of the US Congress, tweeted back to Mr Zarif: “The New Year would be even sweeter if you would end Iran’s Holocaust denial” to which the minister responded: “Iran never denied it. The man who was perceived to be denying it (former president Mahmoud Ahmadinejad) is now gone. Happy New Year.”

This attempt to show empathy towards Jews was somewhat undermined last week by Iran’s Press TV’s report on Prince Charles’s attendance at the installation of the new chief rabbi. The TV station said that the Prince’s “show of allegiance with the jews (sic)” proved the “vast covert links between British royals and the Israeli regime.”

The attention that these Twitter exchanges drew was enough to prompt a comment from Prime Minister Benjamin Netanyahu, who said last Saturday: “I am not impressed by the blessings uttered by a regime that just last week threatened to destroy the state of Israel.”

The European Union’s foreign policy chief, Baroness Catherine Ashton, said last week that she plans to meet Mr Zarif at the UN General Assembly in New York later this month to co-ordinate the next round of nuclear talks.

The discussions between Iran and the five permanent members of the Security Council and Germany over its uranium enrichment programme have been going on for a year.

On another issue, so far, the Obama administration has refused to involve Iran in any talks over Syria’s future.