ISTANBUL (Reuters) - Turkish police raided a television station and a newspaper close to U.S.-based Muslim cleric Fethullah Gulen on Sunday, detaining some people, media reports said, two days after President Tayyip Erdogan signaled a fresh campaign against Gulen's supporters.

Police launched simultaneous operations at various addresses in Istanbul and provinces across Turkey, detaining people including a top executive of a television channel close to Gulen, state broadcaster TRT Haber reported.

Gulen and Erdogan are bitter rivals.

Media reports said arrest warrants were issued for 32 people.

"The free press cannot be silenced," a crowd chanted at the Istanbul offices of newspaper Zaman as editor Ekrem Dumanli made a speech to them broadcast live on television, defiantly calling on police to detain him.

The raids come a year after the emergence of corruption investigations targeting Erdogan's inner circle, which he said were a plot to topple him orchestrated by a "parallel structure" of supporters of Gulen. The cleric, a former ally of Erdogan, denies the charge.

The investigation, which became public with police raids on Dec. 17 last year, led to the resignation of three ministers and prompted Erdogan to purge the state apparatus, reassigning thousands of police and hundreds of judges and prosecutors.

(Additional reporting by Humeyra Pamuk; Writing by Daren Butler, editing by John Stonestreet)