ISTANBUL - Turkey ordered another 47 journalists detained on Wednesday, part of a large-scale crackdown on suspected supporters of U.S.-based Muslim cleric Fethullah Gulen, accused by Ankara of masterminding a failed military coup.

Interior Minister Efkan Ala said more than 15,000 people, including about 10,000 soldiers, had been detained so far over the July 15-16 coup attempt, CNN Turk broadcaster reported. Of those, more than 8,000 were formally arrested pending trial.

Tens of thousands of others suspected of having links to the Gulen movement, including police, judges and teachers, have been suspended or placed under investigation since the coup, which was staged by a faction within the military.

Turkish authorities were planning a major shake-up of the military to remove elements linked to US-based preacher Fethullah Gulen just ahead of the failed coup, a key minister said Wednesday.

Energy Minister Berat Albayrak, who is the son-in-law of President Recep Tayyip Erdogan, suggested parts of the military had wanted to act against the government as they knew they were about to be purged.

Albayrak, who was with Erdogan throughout the night of the botched putsch on July 15, said the president had first been warned about the coup by a civilian and it was only later that the gravity of the situation become clear.

Gulen, who lives in Pennsylvania but whose movement has a wide following in Turkey where it runs a large network of schools, has denied any involvement in the failed coup.

Western governments and human rights groups, while condemning the abortive coup in which at least 246 people were killed and more than 2,000 injured, have expressed concern over the extent of the crackdown, suggesting President Tayyip Erdogan may be using it to stifle dissent and tighten his grip on power.

Erdogan, who narrowly escaped capture and possible death on the night of the coup, denies the crackdown has wider aims and says the Gulen movement threatened democracy by building a "parallel state".

The detention of journalists ordered on Wednesday involved columnists and other staff of the now defunct Zaman newspaper, a government official said. Authorities in March shut down Zaman, widely seen as the Gulen movement's flagship media organisation.

"The prosecutors aren't interested in what individual columnists wrote or said," said the official, who requested anonymity. "At this point, the reasoning is that prominent employees of Zaman are likely to have intimate knowledge of the Gulen network and as such could benefit the investigation." However, the list includes journalists, such as Sahin Alpay, known for their leftist activism who do not share the religious world view of the Gulenist movement. This has fuelled the concerns that the investigation may be turning into a witch-hunt of the president's political opponents.

On Monday, media reported that arrest warrants had been issued for 42 other journalists, 16 of whom have so far been taken into custody.

UN's Ban deeply concerned

by ongoing arrests

UN Secretary-General Ban Ki-moon on Wednesday expressed deep concern about the ongoing wave of arrests in Turkey following the attempted coup.

Ban told Foreign Minister Mevlut Cavusoglu during a telephone conversation that "credible evidence" must be presented swiftly so that the detainees' legal status can be determined by a court of law.

More than 15,000 people including military officials were detained during the massive sweep that followed the July 15 failed coup and at least 8,000 remain in custody.

On Wednesday, Turkish authorities issued arrest warrants for dozens of journalists including 47 former staff of the Zaman daily, one of the country's biggest newspapers.

In his conversation with the foreign minister, Ban "referred to worrying reports of mistreatment and abuse of some of those who are still in custody and their detention conditions, and underscored his deep concern about the scope of continuing widespread arrests, detentions and suspensions," said UN spokesman Farhan Haq.

"Credible evidence on those under investigation has to be presented swiftly to the judicial system so that legal determination could be made before the court of law," he added.

The UN chief said that while he recognized the "extraordinary circumstances prevailing in the country following the coup attempt", he expected Turkey to uphold fundamental rights and to adhere to its international obligations.

Ban has spoken out repeatedly on the need for Turkey to respect freedom of speech and assembly and to uphold due process.

Turkey's Prime Minister Binali Yildirim warned the crackdown and purge unleashed after the coup was not over.

The UN chief "trusts that the government and people of Turkey will transform this moment of uncertainty into a moment of unity, preserving Turkey's democracy," the spokesman added.

Alpay is a former official of Turkey's left-leaning, secularist main opposition CHP party. The Dogan news agency said police raided his home in Istanbul early on Wednesday and detained him after a 2-1/2 hour search of the property.

Separately, Turkey's capital markets board said it had revoked the licence of the head of research at brokerage AK Investment and called for him to face charges over a report he wrote to investors analysing the coup.

Erdogan's ruling Islamist-rooted AK Party and opposition parties, usually bitterly divided, have demonstrated a rare spirit of unity since the abortive coup and are seeking consensus on constitutional amendments partly aimed at "cleansing" the state apparatus of Gulenist supporters.

A senior AK Party official said on Wednesday the parties were discussing plans to increase parliamentary control of a key state body that appoints judges and prosecutors.

Also on Wednesday a government official said Turkish special forces were still hunting in hills around the Mediterranean resort of Marmaris for a group of 11 commandos thought to have tried to capture or kill Erdogan on the night of the coup, when he was on holiday in the area.

In testimony provided following his detention, Major General Mehmet Disli, the brother of a prominent ruling party lawmaker, strongly denied allegations that he was involved in the coup, saying he had been forced by the plotters to mediate with the chief of the military General Staff on July 15.

General Staff head Hulusi Akar was held hostage for hours by the plotters but refused to join their coup.

Erdogan, a popular but polarising figure who has dominated Turkish politics for more than a decade, will chair an annual meeting of the Supreme Military Council (YAS) on Thursday after vowing to restructure the armed forces following the coup.

The military General Staff said 35 planes, including 24 fighter jets, 37 helicopters, 74 tanks and three ships had been used by the coup plotters, NTV reported. It put the number of soldiers from the Gulenist network involved in the putsch attempt at 8,651, about 1.5 percent of the armed forces.

Around a third of Turkey's serving generals have been arrested pending trial since the coup attempt.

In Greece, authorities on Wednesday postponed hearings for eight Turkish soldiers who sought asylum there after fleeing Turkey. The men - three majors, three captains and two sergeant majors - deny being involved in the coup but Turkey has branded them "traitors" and is demanding their extradition.

Erdogan has signalled Turkey might restore the death penalty in the wake of the failed coup, citing strong public support for such a move, though the European Union has made clear this would scupper Ankara's decades-old bid to join the bloc.

Turkish officials have complained of what they perceive as a lack of support from the EU over the coup, while European leaders have urged Ankara to show restraint and a sense of proportion in bringing those responsible to justice.

The attempted coup has also tested Turkey's ties with its Nato ally the United States, where Gulen has lived in self-imposed exile since 1999. Responding to Turkey's request for Gulen's swift extradition, Washington has said Ankara must first provide clear evidence of his involvement in the coup.

Gulen lives in a secluded compound in Pennsylvania's Pocono Mountains, but Erdogan has grounds to worry about the reclusive cleric's reach inside Turkey. In 2013, his followers in the police and judiciary opened a corruption probe into business associates of Erdogan, then prime minister, who denounced the investigations as a foreign plot.

The strains with the EU and the United States have coincided with Turkey's renewed push to repair ties with Russia, badly hurt last November by the Turkish downing of a Russian jet involved in military operations in Syria, and Moscow's subsequent imposition of trade sanctions.

On Wednesday, Deputy Prime Minister Mehmet Simsek said his talks with Russian officials this week on improving bilateral relations had taken place "in a very positive atmosphere".

Simsek, respected by Western investors as a safe pair of hands in guiding the Turkish economy, also said he saw no reason to downgrade Turkey's credit rating following the coup. Standard & Poor's recently downgraded the sovereign debt outlook to negative from stable and Moody's has said it will review the rating for a possible downgrade.