A row over Twitter messages claiming to be from Iranian President Hassan Rouhani has caused confusion over who is writing the accounts in his name.
On Wednesday, a message from one such account wished Jews a happy new year.
Officials were then quoted as saying that he did not have a Twitter account.
However, messages posted on the account in question have thus far been in line with official announcements, prompting speculation that they may be the work of people close to him.
In addition, the fact that Mr Rouhani congratulated Jews on the occasion of Rosh Hashanah would not necessarily be controversial, correspondents say.
Iran has a Jewish community of up to about 30,000, according to some estimates, though much lower than the population which numbered about 80,000 prior to the 1979 Islamic revolution.
The semi-official Fars news agency quoted an official in Mr Rouhani's office as saying: "Mr Rouhani does not have a Twitter account".
Mohammad Reza Sadeq added that during the recent election campaign, some of Mr Rouhani's supporters opened various online accounts using his name and "some of these... may still be active".
However, another message appeared on Thursday morning, also sending Jews greetings on the occasion, this time on a Farsi-language account under Mr Rouhani's name.
Twitter and other social media sites such as Facebook are banned in Iran but can be accessed via proxy servers.
The fact that Twitter is blocked in Iran means that if someone in Mr Rouhani's circle is indeed behind the accounts, he can always officially deny messages that cause controversy, BBC Persian's Rana Rahimpour reports.
Correction 10 September: The estimated size of Iran's Jewish community has been amended in this story.