Turkey detains 20 in coup plan investigation: agency

ISTANBUL (Reuters) - Turkish police detained 20 people on Wednesday in connection with an investigation into an alleged plot to overthrow the government, state-run Anatolian news agency said.

The police raids mark a further widening of the operation against the shadowy, ultra-nationalist Ergenekon organization, which has fuelled a climate of political uncertainty in Turkey and unsettled financial markets.

Eighty-six people have already been charged with involvement in a bid to stage a coup against Prime Minister Tayyip Erdogan's government, which hard-line secularists accuse of Islamist subversion.

Early on Wednesday, police staged simultaneous raids in five provinces from Istanbul in the west to Elazig in eastern Turkey, Anatolian reported.

The operation was focused on the central Turkish province of Konya, where 12 people were held. The remaining detainees were also taken to Konya for questioning.

Detainees include a journalist and senior officials from a small nationalist party whose leader is already in custody, broadcaster CNN Turk reported.

In the last 50 years, military coups have unseated four elected governments in Turkey, a predominantly Muslim but officially secular country seeking to join the European Union.

Some opponents of the government, which denies any secret Islamist agenda, call the controversial coup case revenge for court moves to outlaw the ruling AK Party and ban Erdogan and President Abdullah Gul from party politics.

Istanbul's chief prosecutor filed the indictment last week on the Ergenekon case, which includes forming an armed terror group and attempting to overthrow the government by force. An Istanbul court must decide by July 28 whether to accept the case.

The 86 defendants named in the indictment include the head of a small nationalist party, journalists, and retired army officers.

Earlier this month, two senior retired generals, leading businessmen and journalists, all critical of the AK Party, were arrested and another indictment is being prepared for them.

The case has added to political concerns in Turkey generated by the case to close the AK Party for seeking to introduce Islamic rule. Constitutional Court judges will begin deliberating that case on July 28.

(Editing by Catherine Evans)