Within hours of the start of proceedings at the 11-judge constitutional court to hear a lengthy prosecution argument to outlaw the ruling Justice and Development Party (AKP) on the grounds that it contravenes Turkey's secular system, the authorities arrested a number of people – including two retired generals and a journalist – and held them for questioning over an attempted coup against the AKP government.

Turkish reports differed on the number of people arrested in Ankara and Istanbul early Tuesday, but estimates ranged from seven to 25. The authorities did not issue a statement on their crackdown against an alleged right-wing nationalist secular outlawed group called Ergenekon.

The campaign and investigation against the group, accused of seeking to topple the government, began a year ago. Among the 50 people still in detention include former army officers, journalists, lawyers and politicians. They have yet to be indicted.

The latest two retired four-star generals to be detained, Hursit Tolon and Sener Eruygur, who remained in prominent positions last year, are known for their opposition against the AKP for its Islamist roots.

Reports said police seized the two former generals from their homes in a closed military residential complex, indicating the military institution – which is said to be the protector of the secular regime – was not involved in a coup. Police require permission from the military authorities to enter their zones.

The editor of the anti-government daily Cumhuriyet, Mustafa Balbay, and the head of the Ankara chamber of trade, Sinan Aygun, were among those taken into custody earlier in the day.

Opposition leaders said the timing of the new arrests, before the court was to hear the case against the AKP, was not a coincidence, but insisted that the government was attempting to intimidate its opponents to withdraw their support for the bid to outlaw the ruling party.

Analysts say the court case against the party, led by Prime Minister Recep Tayyip Erdogan, could also be part of a coup against the government, which came to power after the AKP was re-elected in 2007 to a second five-year term with 47 percent of the vote.

Turkey's chief prosecutor, Abdurrahman Yalcinkaya, recited a 90-minute argument to the country's highest judges on why the AKP should be banned, saying the party was gradually replacing an 85-year-old secular system with an Islamic regime.

"The secular republic is facing an unprecedented danger because the counter-revolutionary forces are no longer in the margins, but in government," Yalcinkaya said.

He mentioned the AKP-dominated parliament's decision to amend the constitution to lift a ban on wearing the Islamic headscarf in universities, banning alcohol sales in restaurants run by ruling party municipalities and trying to promote Koranic courses, insisting all these measures indicate a secret Islamic agenda.

The chief prosecutor also urged the tribunal to ban 71 AKP officials, including Erdogan and President Abdullah Gul, from party politics for the next five years.

The government has repeatedly denied having a hidden agenda to overturn the secular regime, but has stressed that repressing religious freedoms was a violation of democracy and free expression.

The AKP will deliver its defense, also in a closed-session hearing, on Thursday.

Nevertheless, it is said to be preparing for the worst, having taken notice of the constitutional court's verdict that last month that threw out parliament's decision to lift the ban on the headscarf.

Since the establishment of the court 45 years ago, it has outlawed 24 parties, including two whose members currently form the majority of the AKP.

But if it rules against the AKP, it would be the first time the court bans a governing party.

The party insists it has renounced its Islamist roots in a bid to improve Turkey's chances of joining the European Union. For its part, the EU is uneasy about the prospect of an elected party being shut down in a country that is aspiring to become a member.

A recent public opinion poll, published by Milliyet newspaper on Monday, showed that the majority of Turks opposed banning the party and believed a decision to do so would trigger unrest in the country.

The survey, whose results indicated the AKP remained the most popular party, also showed that most believed the party's successor would win early elections.

Turkish analysts say if the court bans the party, most of its lawmakers would regroup under a different name and call snap elections before the end of the year.

And if it bars Erdogan from party politics, the analysts expect him to return to parliament by running as an independent and will probably pull the strings of a new party of his old comrades.