TEHRAN: Iran has arrested 11 journalists accused of cooperation with foreign-based, Persian-language media organisations, several chief editors of Iranian outlets said Monday.    

The development is a major escalation in a press crackdown that reflects Iran's zero tolerance for those who work with dissident media or outlets deemed as unfriendly or hostile.

In recent years, Iran has denounced Voice of America and the BBC's Persian service, describing them as arms of US and British intelligence agencies, and has warned of severe repercussions for Iranian journalists and activists caught having contacts with these outlets.

Also, Tehran has repeatedly accused the United States and Britain of seeking to provoke unrest in a bid to oust the country's clerical rulers, and has frequently accused opposition figures and supporters of being in league with the nation's enemies.

Many Iranians regularly tune in to the BBC and VOA's Persian-language radio and TV channels, despite a ban on satellite dishes and government attempts to jam the airwaves.

The chief editors of the arrested journalists told The Associated Press that the 11 were taken into custody late on Sunday because of their ''foreign contacts.''

The editors, who spoke on condition of anonymity because of fears of reprisals, refused to say if the detained were accused of providing material specifically to BBC or VOA.

The arrests followed last week's warning by State Prosecutor Gholam Hossein Mohseni Ejehei who said journalists who are in contact with ''hostile foreign media'' would be punished. Ejehi described such reporters as ''serving the enemy's purpose.''

The detained journalists, seven men and four women, were identified by their editors. They are from six different news organisations, including four daily papers, a weekly and the semi-official ILNA news agency.

Some of them have in the past spent months behind bars over critical writings that were carried by foreign-based Iranian dissident media or writings that supported feminist activities.

One of the editors said three of the arrested were from the reformist daily Etemad. Three others were from the reformist Shargh daily, whose editor said they were arrested at the paper's building.

Another journalist, Saba Azarpeik from the Tejarat-e-Farda weekly, was also missing and feared arrested, according to a colleague, who also spoke on condition of anonymity for fear of reprisals.

Meanwhile, the semiofficial ISNA news agency said Monday that the conservative Tabnak news website, close to the former Revolutionary Guard commander Mohsen Rezaei, has been blocked. No reason was given.

Since 2000, Iran's judiciary has shut down more than 120 pro-reform newspapers and jailed dozens of editors and writers on vague charges of insulting authorities.