ISTANBUL (Reuters) - Turkish police have detained the editor of a newspaper close to an Islamic cleric foe of Tayyip Erdogan on allegations of insulting the president, media reports said, fuelling concerns about a clampdown on media ahead of a Nov. 1 election.

Today's Zaman chief editor Bulent Kenes was detained at its Istanbul offices on Friday after a court issued an arrest warrant in response to a prosecutor's challenge to a court decision not to keep him in custody, Dogan news agency said.

It said a crowd of around 200 people gathered at the offices of the English-language paper and chanted in support of Kenes as he was taken away over allegations of insulting Erdogan on Twitter. The editor had previously given a statement to police on the matter but was released.

Police officials were not immediately available to comment.

Protesters in the crowd held up banners saying "Free media cannot be silenced" as they gathered behind Kenes before he was taken away.

"They are trying to silence the media. This is not befitting Turkey. Our people will never accept this," Kenes was reported as telling the assembled media.

The newspaper is staffed by many supporters of U.S.-based cleric Fethullah Gulen, and it is sympathetic to his views as well as being fiercely critical of the government.

Erdogan accuses Gulen of seeking to overthrow him by means of a "parallel structure" of supporters in the judiciary, police, the media and other institutions.

Gulen has denied such charges and Erdogan's opponents say recent developments are an attempt to silence opposition before the polls, where Erdogan wants the ruling AK Party which he founded to win back the majority which it lost in a June vote.

The government denies trying to silence dissent.

Earlier this week Turkey's largest pay-TV platform removed channels close to Gulen from its services on the order of a prosecutor. Last month prosecutors launched an investigation into Dogan Media Group for alleged "terrorism propaganda".

(Writing by Daren Butler; Editing by Pravin Char)