The Turkish government has vowed to avenge the deaths of 13 soldiers who were ambushed on Thursday by Kurdish rebels, in the deadliest clash between Turks and Kurds in three years.

The incident also killed seven Kurd rebels.

In response, Ankara has deployed soldiers, air force bombers and helicopter gunships in the Kurdish heartland, south-eastern Turkey.

Prime Minister Recep Tayyip Erdogan warned that the Kurdish rebel movement will pay a heavy price for the attack.

Separately, a Kurdish political group has declared democratic autonomy in southeastern Turkey.

As the Kurdish people we declare democratic autonomy, remaining bound to the national unity of the peoples of Turkey, said Aysel Tugluk, deputy chairwoman of the Kurdish Democratic Society Congress (DTK).

The vague term democratic autonomy has so angered the Ankara government that prosecutors could impose criminal charges on DTK members.

Even more ominously, Erdogan has drawn a connection between DTK activists and the outlawed Kurdish PKK militant group.

I'm openly telling the terrorist organization and its extensions that they should never expect any goodwill on our part in the face of such ill-intentioned actions, he said.

If they want peace, there is one thing to do: the terrorist organization [PKK] must lay down arms.”

The mainstream Kurdish political party, the DTP, is boycotting parliament, in protest of the detention of several of its members who won election to parliament in June.