The war of words between Prime Minister Recep Tayyip Erdogan and an Islamic rival he accuses of plotting a coup has taken an increasingly vitriolic turn as the power struggle stokes concerns at home and abroad about the state of democracy in Turkey.
"Empire of fear", "witchhunt", "treachery", "international conspiracy" are some of the words being hurled around in the most damaging crisis in Turkey since Erdogan took office 11 years ago.
The embattled Turkish leader has gone on the offensive in the feud with erstwhile ally Fethullah Gulen but in doing so has raised concerns about what critics fear is an increasingly autocratic government in a country once hailed as a model of Muslim democracy.
The long-festering dispute is at the heart of the graft scandal threatening the Islamic-leaning government with just weeks to go before Turkey votes in local elections in March -- a key test for Erdogan's once unassailable grip on power.
"This fight will go on for years," warned Nihat Ali Ozcan of TOBB university in Ankara.
Erdogan has already launched a mass purge of police and prosecutors involved in the corruption probe, which hit the headlines in December with sweeping police raids that saw the detention of key government allies including business leaders, civil servants and sons of cabinet ministers.
His Justice and Development Party (AKP) is also pushing a bill that would limit the powers of the independent judiciary and put key appointments in the hands of the government, a move that has set alarm bells ringing among key allies in the European Union and the United States.
"We are watching developments with concern," warned one EU diplomat.
But Erdogan has vowed no let-up in the campaign against loyalists of the exiled Islamic preacher, who could play a vital role in determining the AKP's performance at the ballot box in March without even putting forward a candidate.
"This is an asymmetric war: Erdogan is the leader of a political party. He is quite visible and legitimate. But the Gulen movement is not transparent and the boundaries of its structure are not very clear," said Ozcan.
Although based in the United States where Gulen has lived in exile since 1999, his Hizmet (Service) network wields enormous influence in Turkey through various state apparatus, particularly the police and judiciary, and a string of media outlets, businesses, universities and thinktanks.
Erdogan went on the warpath again on Wednesday, instructing Turkish ambassadors to tell the world about what he labelled an "empire of fear" created by the Gulen movement.
"That organisation and its allies in the media are trying to deal a heavy blow to the economy, hike interest rates, scare foreign investors, sabotage energy policies, and taint Turkey's image abroad," Erdogan thundered.
The Turkish strongman has pointedly refrained from ever naming Gulen, whose organisation was once a vital part of his broad power base and helped the AKP to three successive election victories since 2003.
"The target here is not the government or the party but the country and its national interests," he said. "It cannot be explained other than treachery."
The crisis is jeopardising Turkey's economic success story, with the national currency the lira tumbling to all-time lows and growth forecasts under threat.
Gulen supporters have retaliated defiantly to the allegations however, accusing the government of conducting a "witchhunt" against the movement.
"There is an ongoing campaign of McCarthyism in the police department that cannot even be compared to things done during the coup years," columnist Hasan Cemal wrote in Today's Zaman, a newspaper funded by Gulen.
"Similar to how democracy was undermined by allegations of communism during the Cold War years... democracy and the rule of law are now being undermined by allegations of Gulenism."
The AKP and Hizmet movement share similar conservative political and religious views and were once close allies, both eager to clip the wings of the powerful military, which has waged several coups in Turkey as the self-declared guardians of the secular state.
But cracks emerged in the alliance over Erdogan's tough stance against the wave of anti-government protests in June and their feud spilled out into the open in November when the government unveiled plans to shut a network of private schools run by Hizmet.
Cemal Usak, vice president of Gulen mouthpiece the Foundation of Journalists and Writers, said accusations that the movement was operating a "state within a state" were "completely absurd and false".
He said the AKP and Gulen had long been united because of their adherence to common values.
"But in recent years, the AKP has chosen to pursue other avenues we so we have had a 'falling out of love'," he told AFP in a recent interview.
"The Hizmet movement will not do what it has always refused to do -- to say 'you have to give your vote to this or that party'," Usak said. "But I, as a journalist, can tell you that the movement will not, as it has in the past, give its support to the ruling power."