TEHRAN: Authorities in Iran have arrested 11 journalists accused of cooperation with foreign-based, Persian-language media organizations.

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

The chief editors of the arrested journalists told The Associated Press on Monday that the 11 were taken into custody late on Sunday because of their "foreign contacts." They are from six different news organizations, including four daily papers, a weekly and the semi-official ILNA news agency.

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