The Democratic Society Party, which won 20 seats in parliament in July, last week called for autonomy for Kurds living in the country's southeast. The call came amid tension over how to deal with separatist Kurdish rebels, with the military preparing for a possible cross-border offensive against their bases in northern Iraq.

Chief Prosecutor Abdurrahman Yalcinkaya said in a statement "that speeches and actions by party leaders have proved that the party has become a focal point of activities against the sovereignty of the state and indivisible unity of the country and the nation."

He said a legal case was launched in an effort to shut down the party.

The prosecutor's office will send an indictment to the country's Constitutional Court for a trial. Several predecessors of the pro-Kurdish party were banned by Turkey's Constitutional Court on similar grounds and for alleged ties to rebels.

The party demanded more rights for the Kurdish minority and autonomy for Kurds living in the southeast during a party congress last week.

"It is envisaged that each autonomous section is represented with its own colors and symbols and creates its own democratic administration, although the national flag and official language remain valid for the entire nation of Turkey," the party said in a statement last week.

Selahatin Demirtas, a legislator from the pro-Kurdish party, said Friday that banning it would only aggravate the Kurdish problem, the Dogan news agency reported.

Turkish leaders have accused the pro-Kurdish party of having ties to the rebel Kurdistan Workers' Party, or PKK. Turkish leaders insist the party should declare the PKK a terrorist organization to prove its allegiance to Turkey. Both the U.S. and the European Union have labeled the PKK a terrorist organization.

DEHAP, the predecessor of the present party, dissolved itself in 2005 as prosecutors tried to close it. The constitutional court closed down four previous pro-Kurdish parties.

Yalcinkaya accused leaders of the current party of dissolving DEHAP and establishing the new party under orders from imprisoned Kurdish rebel chief Abdullah Ocalan, who is serving life on a prison island near Istanbul.

"By implementing orders they received from the leader of a terrorist organization in prison, (they) have openly shown their allegiance to the terrorist organization and its leader," Yalcinkaya said.