A woman waves flags during a pro-Erdogan rally in Taksim square in Istanbul on Friday following the failed military coup attempt of July 15. Turkey detained 283 members of the presidential guard of Recep Tayyip Erdogan after last week's attempted coup, a government official said. Photo: AFP

Turkey readied Sunday for its first cross-party rally against the bloody putsch attempt, following the breakup of Recep Tayyip Erdogan's presidential guard as sweeping purges of suspected state enemies continue.

The mass rally, to be held under tight security on Istanbul's iconic Taksim square, was called by the biggest opposition group, the secular and center-left Republican People's Party.

But in a show of patriotic post-coup unity, it will be joined by Erdogan's ruling Islamic-conservative AKP party, whose followers have covered city squares in seas of red Turkish crescent flags every night since the failed coup.

Sunday's mass event, expected to be boosted by free public transport in the city of 15 million, will seek to soothe divisions after the shock of the July 15 coup and the subsequent government crackdown.

"The Turkish republic is stronger than it was in the past," wrote Prime Minister Binali Yildirim in an editorial in the HaberTurk daily.

"Turkey is on democracy watch ... This watch continues until the anti-democratic elements are cleaned out," he said.

The number of alleged conspirators who have been rounded up has surged above 13,000 with soldiers, police, justice officials and civilians all targeted in a crackdown that has alarmed European leaders. Erdogan claims that the conspiracy was orchestrated by a political opponent and former ally, Fethullah Gulan, a resident of the US since 1999.

Turkey has undergone a seismic shift since the night of violence when renegade soldiers sought to topple Erdogan but were stopped by crowds of civilians and loyalist soldiers and police in clashes that claimed 270 lives. In the latest reaction to the coup, Yildirim said Turkey would disband the 2,500-strong Presidential Guard, saying there was "no need" for the elite regiment.

Almost 300 of its officers have been detained after some of them forced TV news presenters to read statements stating that martial law had been declared during the abortive coup attempt.

Under new police powers decreed as part of a three-month state of emergency, all those detained can be held without charge for 30 days.