Turkish authorities seized control of a newspaper linked to Islamic cleric Fethullah Gulen on Friday, in a widening crackdown against supporters of the US-based foe of President Tayyip Erdogan.Administrators have been appointed to run the Zaman newspaper at the request of an Istanbul prosecutor, state-run Anadolu Agency reported. It was unclear how the paper's sister publications, including the English-language Today's Zaman, would be affected.The move against Zaman came hours after police detained prominent businessmen over allegations of financing Gulen's group, according to separate reports from Dogan news agency.Erdogan accuses Gulen of conspiring to overthrow the government by building a network of supporters in the judiciary, police and media.Staff at Today's Zaman were rushing to put out the next edition of the paper before administrators arrived, editor-in-chief Sevgi Akarcesme told Reuters."This means the practical end of media freedom in Turkey. The media has always been under pressure, but it has never been so blatant," she said."Taking over a newspaper is against the constitution, especially since there are no grounds for it. This amounts to the suspension of the constitution."Authorities have seized and shut down opposition media outlets associated with the Gulen movement before. The state deposit insurance fund this week said an Islamic bank founded by Gulen followers might be liquidated within months. Dogan reported that police detained Memduh Boydak, chief executive of furniture-to-cables conglomerate Boydak Holding, as well as the group's chairman Haci Boydak and two board members.Nobody from the company, based in the central Turkish city of Kayseri, was available to comment.Erdogan has led the crackdown against once-influential followers of his former ally, after police and prosecutors seen as sympathetic to the cleric opened a corruption investigation into Erdogan's inner circle in 2013.Erdogan has accused Gulen of operating a "parallel state structure" bent on toppling him.