Iran has arrested and taken into custody nearly a dozen journalists, accusing them of cooperation with foreign news outlets.

The Islamic Republic claimed the reporters were collaborating with foreign-based, Persian-language media organizations.

The journalists are members of six different news organizations, including four daily newspapers, a weekly and the semi-official ILNA news agency.

The chief editors of the arrested journalists told The Associated Press on Monday they were detained late Sunday because of their “foreign contacts.”

Over the past several years, Iran has denounced the British Broadcasting System (BBC)’s Persian language service, and the Voice of America. 

Tehran claims both are arms of the British MI5 and U.S. CIA intelligence agencies, and has warned that journalists – and activists – will face severe consequences if they found to have had any contact with them.

The move is considered a major escalation in censorship in Iran, and a crackdown to show the government’s zero tolerance policy for those who collaborate with dissident media or outlets deemed unfriendly, the Lebanon-based Daily Star commented on Monday.

In June 2011, Iranian photojournalist Mariam Majd was arrested in Tehran just days before she was scheduled to leave for Germany, where she was invited to visit Berlin by Deutsche Welle, Germany’s international broadcasting service. 

Just a few weeks prior, acclaimed documentary filmmaker Mahnaz Mohammadi and journalist Zahra Yazdani were arrested, as well a number of human rights activists. Both were reportedly being held at Evin Prison, according to an activist blog.

Their fate is still unknown.