A crackdown on corruption in Turkey is exposing a growing rift between the government and an influential Muslim leader, striking at the very heart of Turkish politics.

High profile figures close to Prime Minister Recep Tayyip Erdogan have been arrested, and the government has retaliated by sacking senior police officers involved.

Erdogan has described the graft investigation as a "dirty operation" against his government. Others are viewing it as the most audacious challenge yet to his rule.

It's a power struggle ... the two [Erdogan and Gulen] had joined forces in order to fight 'the common enemy' ... being the military, judicial, staunchly Kamalist secularist elite in Turkey. Since they have weakened, now they don't have this common ground to meet, and now it's about whose weight is going to carry more on certain policy decisions.

Barcin Yinanc, op-ed editor at the Hurriyet Daily News

The events have focused attention on the feud between Erdogan and the powerful cleric, Fethullah Gulen, whose network of followers hold influential positions in institutions from the police and secret services to the judiciary.

Erdogan has accused the network of trying to create "a state within a state". Reacting to the arrest of prominent figures, he said: "Those who are receiving the support of financial circles and the media cannot change the direction of this country. Those who are supported by dark circles, from inside and outside the country, cannot change the direction of Turkey."

"The ones who are backed by dark internal and external forces cannot change the direction of Turkey. Turkey is not a country that can have operations or surgeries performed on it," Erdogan continued.

Reporting from Istanbul, Al Jazeera correspondent Anita McNaught said: "Something else is going on in Turkey alongside allegations and counter-allegations of corruption. That something else is the movement led by Muslim leader Fethullah Gulen."

"His education foundation has helped Turkish influence around the world, and built him a respected power base at home," she added.

Gulen is leader of a moderate Islamic group known as Hizmet. He has lived in self-imposed exile in the US since 1999.

His movement is known for its network of hundreds of schools in more than 140 countries across Africa, the Middle East, Asia and the US, but it is in Turkey where its power really lies. Gulen followers serve in government institutions, the media, and even the ruling AK Party itself.

Gulen previously backed the AK Party to three successive election victories, but the relationship seems to have gone sour, with Erdogan's recent move to shut down private schools run by the Hizmet movement being seen as a declaration of war on Gulen.

So, is this simply a battle of wills between two powerful figures, or is the corruption investigation exposing fundamental fault lines which could change the face of Turkish politics? And how will this all play out in local and presidential elections due to take place next year?

To discuss this, Inside Story presenter, Shiulie Ghosh, is joined by guests: Taha Ozhan, the director of SETA - the Foundation for Political, Economic, and Social Research - a Turkish-based international think tank; Fadi Hakura, an associate fellow at Chatham House specialising in Turkish politics; and Barcin Yinanc, op-ed editor at the Hurriyet Daily News.

"I think Prime Minister Erdogan has the state resources ... to drag this fight forward. The question is what impact will it have on Prime Minister Erdogan and on the broader Islamic movement in Turkey? The outcome of this battle will tarnish, and lead to some poisonous divides within the Islamic movement, and that could undermine popularity for the movement going forward."  

- Fadi Hakura, an associate fellow at Chatham House specialising in Turkish politics

Source: Al Jazeera