Turkey on Wednesday began freeing the first of some 38,000 prisoners not linked to the failed coup who are to be released in a move aimed at relieving pressure on prisons overcrowded with putsch suspects.

The parole decision came as Turkey presses on with the biggest purge in its modern history after the July 15 bid by rogue elements in the military to oust President Recep Tayyip Erdogan from power.

Justice Minister Bekir Bozdag said the release was "not an amnesty" but the measure could eventually apply to almost half of the Turkish prison population which has swelled to over 200,000 since the attempted coup.

It will not apply to convicts guilty of murder, terrorism or state security crimes, or the thousands detained after the putsch.

"The regulation refers to crimes committed before July 1, 2016. The crimes committed after July 1, 2016 are outside its scope," Bozdag said on Twitter.

"As a result of this regulation, approximately 38,000 people will be released from closed and open prisons at the first stage."

According to Turkish officials, over 35,000 people have been detained since the coup attempt although almost 11,600 of them have since been released.

- 'Prisons jam-packed' -

The state-run Anadolu Agency said the first convicts began to be released from Istanbul's Silviri prison hours after the announcement.

One of the freed prisoners Turgay Aydin, was quoted as thanking Erdogan and saying: "I am very happy because I am released from prison. I was not expecting it."

Bozdag said in an interview with A-Haber television that the parole could in the end apply to 99,000 out of Turkey's current total prison population of 214,000.

According to Anadolu, the total capacity of Turkey's prisons is for 187,351 people.

Hurriyet columnist Akif Beki wrote on August 11 that "prisons are jam-packed" amid the post-coup purge and asked: "How can that many be arrested without making any space?"

Turkey is in the throes of a three-month state of emergency imposed after the coup, which the authorities describe as an attempt by the US-based preacher Fethullah Gulen to overthrow the existing order.

Gulen vehemently rejects the charges but Turkey has embarked on a relentless drive to expel what Erdogan calls his "virus" from all public institutions.

In the latest move Wednesday, the authorities fired another 2,692 civil servants mostly from the police, the official gazette announced. Some 75,000 people have already been dismissed from their jobs over alleged links to Gulen.

- 'Don't lose Turkey' -

Turkey has pressed the United States to extradite Gulen to face trial back home, with prosecutors already demanding a symbolically tough punishment of two life sentences and 1,900 years in jail.

US Vice President Joe Biden will travel to Ankara next week, the White House announced, in the highest ranking visit to Turkey by any Western official since the coup.

Turkey has been deeply upset by what it has described as the lack of solidarity shown by Western leaders in the wake of the coup bid and is sure to press Biden on the extradition issue.

"If the US does not send him (Gulen) to Turkey, relations will not be the same as they were before July 15," Bozdag said, warning Washington not to "lose" the Turkish people.

And in the latest dispute between Berlin and Ankara, the Turkish foreign ministry reacted angrily to a leaked German government document that described Turkey as a "platform" for Islamists.

With concern also surging over the authorities' attitude on press freedom, security forces sealed and raided the premises of the pro-Kurdish daily Ozgur Gundem following a court order to shut it down.

A Turkish official said the closure had nothing to do with the state of emergency but was because the court found the paper was acting as a mouthpiece for the outlawed Kurdistan Workers' Party (PKK).

Ozgur Gudem said in a statement on its website that two dozen people were detained in the police raid.

Meanwhile, one of the paper's board members Asli Erdogan -- a prominent writer -- was detained in a police raid on her home, Turkish media said.

However the paper still managed to distribute a four-page edition, with the headline "We will not give in."