ISTANBUL (Reuters) - A Turkish prosecutor has issued detention warrants for 53 active sergeants over alleged links to the U.S.-based cleric accused of orchestrating last year s attempted coup, state media said on Tuesday. Twenty of the suspects have so far been detained in the operation across 12 provinces, state run Anadolu Agency said. Thirty-three other soldiers were currently being sought, it said. The interior ministry said on Monday that nearly 700 people had been detained over the previous week on allegations of ties to what Ankara calls the  Gulenist Terror Group . Some 50,000 people have been arrested since the failed putsch in July and around 150,000 dismissed or suspended, including soldiers, police, teachers and public servants, over alleged links with the movement of U.S-based cleric Fethullah Gulen. Gulen, who has lived in self-imposed exile in Pennsylvania since 1999, has denied the charge and condemned the coup. Rights groups and some Western allies fear President Tayyip Erdogan is using the coup as a pretext to stifle dissent. The government argues the crackdown is necessary due to the gravity of the coup attempt, which killed 240 people on July 15, 2016. 