Iran's Writers Association has said in a statement that a number of prominent publishing houses have been banned from attending the fair and the licenses of several have been cancelled. According to the statement, several of the publishers have also been summoned by security officials.
Censorship in the Islamic Republic is nothing new, but as the Writers Association points out, the summoning of publishers and revoking licenses is unprecedented.
The group has condemned the state pressure on independent book publishers and warned about the "increased censorship and cultural crackdown" in Iran.
Iranian news websites report that only books that have been published since President Mahmud Ahmadinejad took power in 2005 have been allowed to be presented at the book fair.
The "Bamdadkhabar" website cites a report by the ILNA news agency according to which books by renowned Iranian writer and critic Houshang Golshiri and prominent female poet Forough Farokhzad have been banned at the fair.
Books by Iranian reformist cleric and currently visiting research professor at America's Duke University, Mohsen Kadivar, have also reportedly been banned at the fair.
"Bamdadkhabar" quoted an unnamed publisher, who did not want to be named because of security fears, as saying that authorities have warned against political discussions and "propaganda against the system" at the booths and said they will be dealt with in "a tougher manner than one can imagine."
"Khabaronline" also reported that on the first day of the book fair all books related to the late Grand Ayatollah Montazeri and Ayatollah Sanei were collected from various stalls and were being kept at the cultural office of Tehran's Mosala, where the book fair is being held.
Ayatollah Montazeri, who passed away last year, was seen as the spiritual father of Iran's opposition Green Movement. Ayatollah Sanei is a senior reformist cleric in Qom who has come under attack by the hard-liners for supporting the opposition movement and condemning the postelection crackdown.
Meanwhile, the "Tehran Times" reports that the Egyptian pavilion was shut down at the book fair for offering a book that referred to the Persian Gulf as the "Arabian Gulf."
Tehran Police Chief Hossein Sajedinia said that police disguised as visitors stumbled upon a book entitled "Arabian Gulf Encyclopedia," which was on display in the Egyptian pavilion.
"Consequently, the pavilion was shut down and police forces recovered the distributed copies of the book with the help of the book fair officials and judicial authorities," he was quoted as saying.
Most countries and international organizations use the name "Persian Gulf" to refer to the waters lying between the Arabian Peninsula and the Iranian plateau. Iran insists that the name "Persian Gulf" should be used but Arab countries tend to refer to it as the "Arabian Gulf" leading to anger and condemnation by the Iranian government and regular Iranians.