Even in a country which regularly holds the world record for jailing journalists, the case of Turkish investigative reporter Baris Pehlivan stands out.

Pehlivan -- whose latest book accused Turkey's last interior minister of having links with organised crime -- is about to be locked up for the fifth time in three years.

Having been jailed, released on parole and locked up again, this time Pehlivan has been ordered back behind bars by text message.

The order has been widely condemned, with 19 international human rights and media freedom organisations uniting to decry "the repeated judicial harassment of Pehlivan, who is exercising his fundamental right to free speech as a journalist.

"Pehlivan has already been incarcerated four times due to his journalism, two of those... for the same sentence," they added. "This order would mark his fifth time behind bars."

The journalist said he was informed by the Turkish justice ministry on August 2 that he had to turn himself in at the Marmara Detention Centre, formerly known as Silivri prison, where many of the critics of Turkey's government are held, on August 15.

Pehlivan and six other journalists were sentenced to three years and nine months in prison in 2021 for reporting the funeral of a member of Turkey's MIT secret services who was operating in Libya, where Ankara supports the UN-recognised Tripoli government.

While his death has never been denied by the Turkish authorities, the reporters were charged with revealing "state secrets".

- 'Abusive prosecutions' -

Pehlivan, editor in chief of the OdaTV website and a contributor to the secular daily Cumhuriyet, was conditionally freed on May 15, then sent back to jail for a day after multiple cases were opened against him.

On Wednesday, Turkey's justice minister cancelled a meeting with the main opposition party about the case at the last minute, to the fury of the CHP MPs.

"A few minutes before the meeting, the minister announced that he had something very important to do," said CHP MP Ali Mahir Basarir.

Pehlivan -- whose name means wrestler in Turkish -- said he was resigned to turning himself in "for the fifth time".

"I have neither killed nor raped anyone," he wrote on Twitter, now known as X. "I have never sold anyone drugs."

In its open letter to the Turkish government, press freedom groups including PEN International and Reporters Without Borders (RSF) called upon Ankara to "reverse the decision to reimprison Pehlivan and end the systematic judicial harassment against him and other journalists."

It also highlighted how the journalist was targeted after co-writing a book, "SS", about the then interior minister Suleyman Soylu, in which he accused him of "having ties to organised crime".

The press freedom groups said Pehlivan's parole was revoked before he was even charged with insulting Soylu, who is deputy chairman of President Recep Tayyip Erdogan's AK Party.

Soylu has denied being linked to the Turkish mafia despite being named by exiled mob leader Sedat Peker in a series of sensational YouTube videos, which detailed alleged ties between politicians and the criminal underworld.

RSF's Erol Onderoglu said the "threat of prison hangs over the press at every turn" in Turkey, which came 165th out of 180 countries in its latest press freedom index.

Pehlivan "should not spend another day in prison", he told AFP. "The truth is that he is constantly the victim of abusive prosecutions."

Twenty journalists remain behind bars in Turkey despite 15 being released last month, according to press freedom groups.