Iran's chief of police criticized officials on Monday for using blocked social networking sites, an indication that resistance remains against government plans to relax restrictions on such websites.

Since his election in June, President Hassan Rohani has developed a significant presence on Twitter to promote his messages in both English and Persian. Foreign Minister Mohammad Javad Zarif also updates his Facebook and Twitter pages regularly.

Their actions have raised hopes among Iranians that social networking sites could soon be unblocked, allowing them to access their accounts without needing proxy servers to trick internet providers into believing they live elsewhere.

"The manner in which some officials have slowly started to cross the red line and enter into areas that citizens are prohibited from using is not a good thing and everyone must be compliant in this field," ISNA news agency quoted Esmail Ahmadi-Moqadam as saying.

Since his election, Rohani has repeatedly indicated his desire to see greater internet freedoms for Iranians and a less strict atmosphere.

The blocking of social networking forums dates back to 2009, when Twitter was often used to organize anti-government protests after the disputed re-election of former president Mahmoud Ahmadinejad.

Those disturbances threatened the very existence of the Islamic Republic of Iran and any move to amend the tight controls will therefore need the approval of influential figures including the head of security agencies and Supreme Leader, Ayatollah Ali Khamenei.

Khamenei himself has a significant presence on social media, which is run by his public relations team.

Judiciary spokesman Gholamhossein Mohseni-Ejei said separately on Monday that social networking sites, namely Facebook, were used to "promote corruption and prostitution", and contravened public morals and safety.

"For this reason, we are against this social network, and if each of these social networks is prepared to erase criminal acts, we will have no problem with membership," state news agency IRNA quoted him as saying.