The chief prosecutor wants to ban Prime Minister Erdogan from politics
Turkey's chief prosecutor has appeared before the country's Constitutional Court calling for the governing party to be closed down.
Founded by Turkish Prime Minister Recep Tayyip Erdogan, the Justice and Development Party, the AKP, won a landslide victory in the last election.
But its critics say it is trying to impose Sharia law on the secular state.
The party's attempt to ease a ban on the wearing of the Islamic headscarf is expected to be central to the evidence.
Prosecutor Abdurraham Yalcinkaya, who has argued that the party has become the focal point of anti-secular activities in Turkey, is appearing before judges in a closed-door session.
"This risk has been increasing every day" reads the 162-page petition submitted to the Constitutional Court by Mr Yalcinkaya.
"The danger is clear and concrete. There is no other way to protect society than to close the party down," it reads.
He is calling for the prime minister, president and 69 other party members to be banned from politics.
The AKP has condemned the case as an assault on democracy. A team representing the party are expected to present their defence on Thursday.
The EU Enlargement Commissioner Olli Rehn has warned the case could jeopardise Turkey's bid to join the bloc - arguing such disputes should be resolved through the ballot box, not the courts.
The AKP was formed after a previous pro-Islamic party was banned. Its founders have since steered a moderate path, pursuing democratic reforms and directing Turkey towards the EU, says the BBC's Sarah Rainsford.
But they spent their political youth in the ranks of an overtly Islamist movement - and ardent secularists do not believe their views have changed.
As the hearing opened, Turkish media said police had made a series of arrests of people believed to be linked to an anti-government network.
Two retired generals and a senior journalist were detained during an early morning swoop which broadcasters said was part of an investigation into an ultra-nationalist grouping called Ergenekon.
The group is reported to have planned political disturbances and is accused of trying to organise a coup against the government. The police have made no official comment on the arrests.