ANKARA - President Recep Tayyip Erdogan on Friday angrily accused a top US general of siding with Turkey's coup plotters for saying the country's turmoil could downgrade military cooperation with Washington.

 The commander of US forces in the Middle East denied Friday that he had any link to the military coup attempt in Turkey. "Any reporting that I had anything to do with the recent unsuccessful coup attempt in Turkey is unfortunate and completely inaccurate," General Joseph Votel, commander of US Central Command, said in a statement.

Turkey has arrested nearly half of its 358 generals for complicity in the July 15 failed putsch, forcing a sudden reshuffle at the top of the armed forces and raising fears over the continuity of its military strategy.

Quoted by US media, US Central Command chief General Joseph Votel said Thursday that the coup bid and subsequent round-up of dozens of generals could affect American military cooperation with Turkey.

"You are taking the side of coup plotters instead of thanking this state for defeating the coup attempt," Erdogan said in angry remarks at a military centre in Golbasi outside Ankara, where air strikes left dozens dead during the coup. "You reveal yourself with your remarks. We will not play your game!" said Erdogan.

In particular, Votel suggested the US had lost crucial Turkish military interlocutors who are now in jail and accused of being behind the coup - a concern echoed by the US head of National Intelligence James Clapper. "Know your place!" Erdogan told Votel, using one of his favourite expressions of anger.

"The coup plotter is already in your country, you are already feeding him," he said in reference to US-based cleric Fethullah Gulen, whom Ankara accuses of masterminding of the coup and wants to see extradited from the United States.

Turkey, which has itself been hit by deadly attacks blamed on militants, regularly targets IS positions in Syria with artillery fire. But adding to the complexities in an already sensitive relationship, Incirlik was an important base for the coup plotters and its commander General Bekir Ercan Van was subsequently arrested.

Turkish Labour Minister Suleyman Soylu even suggested that the United States was behind the coup in the fellow NATO member, but this view has not been echoed by more senior figures.

"Why such a rumour would still be propagated or still be able to find purchase over there, I couldn't begin to guess," said State Department spokesman John Kirby.

Foreign Minister Mevlut Cavusoglu told reporters in Ankara that the notion the consequences of the coup would undermine the armed forces in the fight against IS were "ridiculous" and "unfortunate".

Turkey has embarked on a major crackdown since the rebellion to eradicate what Erdogan call the "virus" of Gulen from every public institution and particularly the army. The government has ordered the discharge of 149 generals for complicity in the putsch, but Cavusoglu insisted the resulting army would be "more dynamic, cleaner and more effective".

Meanwhile, Turkish authorities on Friday widened their post-coup crackdown to the business sector, detaining three top tycoons as part of investigations into the activities of US-based preacher Fethullah Gulen.

Johannes Hahn said he needed to see "black-and-white facts about how these people are treated".  "And if there is even the slightest doubt that the (treatment) is improper, then the consequences will be inevitable," he told German daily Sueddeutsche Zeitung.

Following a shake-up of the military on Thursday after nearly half of its 358 generals were sacked, the top brass of the reshuffled armed forces met Erdogan at his presidential palace in Ankara.

Ninety-nine colonels have been promoted to generals and admirals, although Chief of staff General Hulusi Akar - who was held hostage during the coup attempt - stayed in his post along with the heads of the navy, land and air forces.

Turkey insisted its military would keep up the fight against Islamic State (IS) militants and other militants, saying the armed forces would emerge stronger from the purge.

"When we weed them (pro-Gulenist elements) out, our army will first of all be more dynamic, cleaner and more effective," Foreign Minister Mevlut Cavusoglu said, dismissing concerns that the forces would be weakened.

Meanwhile the probe into coup plotters shifted focus to the financing of Gulen's activities in Turkey, with what appeared to be the first major arrests targeting the business world.

Security forces in the central city of Kayseri detained the chairman of the family-owned Boydak Holding company, Mustafa Boydak, and two other top executives, state-run Anadolu news agency said.

He and the two other executives - Sukru and Halit Boydak - were detained at their homes. Efforts were continuing to detain former chairman Haci Boydak as well as Ilyas and Bekir Boydak, for whom warrants have also been issued.

Mustafa Boydak is also the head of the chamber of commerce in Kayseri, a fast-growing city dubbed one of the "Anatolian Tigers" for the growth and prosperity it has enjoyed under Erdogan's rule.

Family-owned holding companies form the backbone of the corporate economy in Turkey, and Boydak Holding has interests in furniture, energy and finance. It notably owns the prominent Istikbal and Bellona furniture firms.

The nationwide crackdown has also sought to wipe out Gulen supporters from the legal system, media, education and civil service.

Gulen himself, in self-imposed exile since 1999, strongly denies the charges against him and has called on the United States to resist Ankara's pressure for his extradition.

The 21 reporters appearing in court were among dozens of journalists and former newspaper staff issued with arrest warrants earlier this week, to the anger of rights groups.

They included prominent journalists such as the former columnist for the Sabah daily Nazli Ilicak and the commentator Bulent Mumay.

Bur Cavusoglu defended the detentions, saying: "It is necessary to make a distinction between those who carried out the coup and who are engaged in real journalism."

Authorities have also ordered the closure of a total of 131 newspapers, TV channels and other media outlets under the three-month state of emergency declared in the wake of the coup.

Erdogan, who has dominated the country for 13 years, survived the coup thanks to his supporters who took to the streets to counter rebel troops in tanks and warplanes. The clashes left 270 people dead.