Turkey on Friday detained almost 300 members of President Recep Tayyip Erdogan's guard and began shaking up the security forces one week after a failed coup, as US President Barack Obama denied having any prior intelligence of the putsch.

Supporters celebrated the coup's failure to unseat Erdogan, but the Turkish strongman faced growing global criticism over the mass detentions and sackings of tens of thousands of people.

In the latest swoop, Turkey detained 283 members of the presidential guard, an official said, There are at least 2,500 members of the guard, according to local media.

Meanwhile, the Turkish government has cancelled 10,856 passports mainly of state officials "due to flight risk with the holders either in custody or on the run," the official said.

In the most significant institutional changes since the coup, powerful Interior Minister Efkan Ala said the gendarmerie would in future be part of the interior ministry and not the army.

The gendarmerie, which looks after domestic security, had always been part of the military and its removal is a blow to the armed forces' clout after the coup.

"The gendarmerie will definitely be dependent entirely on the interior ministry," Ala said, quoted by the state-run Anadolu news agency.

- 'Intelligence failures' -

Erdogan held a two-hour meeting with the head of Turkey's National Intelligence Agency (MIT) Hakan Fidan at the presidential palace, Turkish television said.

Fidan, a key figure in modern Turkey, is under pressure after Erdogan repeatedly identified intelligence weaknesses during the coup bid.

On Wednesday, the president admitted there had been "intelligence failures", saying he learned about the coup from his brother-in-law.

Authorities imposed a state of emergency on Thursday, strengthening powers to round up suspects behind the failed putsch and suspending the European Convention on Human Rights.

Turkey's Western allies have been watching with alarm the turmoil in the key NATO member state, which has also been reeling from a wave of bomb attacks by Islamic State group jihadists and Kurdish rebels.

"Turkey is a state of law and does not act by revenge," said Prime Minister Binali Yildirim as he visited a military centre in Golbasi outside Ankara, where bombings on the night of the coup killed dozens of people.

"Turkey will not do what they (the plotters) have done. We will act with justice but not a single drop of blood spilt will remain without consequences."

Erdogan said 10,410 people had so far been detained with 4,060 of them remanded in custody, including more than 100 generals and admirals.

Deputy Prime Minister Numan Kurtulmus said there would be no curfews, and that the special measures may only last 45 days, insisting: "We want to end the state of emergency as soon as possible".

"This is not a declaration of martial law," he said.

Justice Minister Bekir Bozdag told CNN-Turk that the period of pre-charge detention would be lengthened.

Selahattin Demirtas, the co-chairman of the pro-Kurdish Peoples' Democratic Party (HDP), told AFP in an interview he feared the a state of emergency could be used for a wider crackdown beyond the coup plotters.

"We voted against the state of emergency because we have no confidence in the AKP (ruling Justice and Development Party) on this subject," he said.

- 'Show us evidence' -

The president blames the coup, which saw seized fighter jets bomb Ankara and tanks run amok in Istanbul, on loyalists of the US-based Islamic preacher Fethullah Gulen.

Turkey has demanded his extradition and the case has raised tensions in already strained relations between Washington and Ankara.

Obama on Friday flatly rejected reports that the United States had prior intelligence, calling such suggestions "unequivocally false."

Obama also told reporters that Turkey's request for Gulen's extradition would be handled in accordance with US law and that "evidence" of wrongdoing by the preacher would be taken seriously.

Obama said that in order for the United States to consider extraditing Gulen, who lives in Pennsylvania, Turkey would have to provide evidence he was involved in last week's attempted coup.

Twenty-eight people were detained in a nationwide operation against individuals suspected to be behind an allegedly pro-Gulen Twitter account called Fuat Avni, which claims to spill key state secrets, the Dogan news agency reported.

Erdogan has basked in the support of jubilant crowds who took to the streets of Istanbul Thursday night, packing one of the bridges spanning the Bosphorus and closing it to traffic.

The president has said July 15 would in future be marked as the "Remembrance Day of the Martyrs".

The government said the coup claimed the lives of 24 plotters, and of 241 citizens and members of the security forces who stood up to them.