Riot police used tear gas and water cannons against a crowd of some 1,000 people who gathered outside the offices of the Democratic Society Party (DTP) in Diyarbakir, the largest city of the Kurdish-majority southeast, after the court announced its ruling in Ankara.

"Blood for blood! Revenge!" the crowd shouted, chanting also slogans praising jailed Kurdish rebel leader Abdullah Ocalan.

Some protestors hurled petrol bombs at the police and targeted them with slings, also smashing the security cameras of nearby banks.

The constitutional court outlawed the DTP on the ground it was linked to Ocalan's Kurdistan Workers' Party (PKK), which has waged a bloody 25-year insurgency in the southeast and is listed as a terrorist group by Ankara and much of the international community.

A crowd of about 100 protestors also gathered at the DTP office in Istanbul, Turkey's largest city which is home to a sizeable Kurdish migrant community, brandishing a banner that read "An End to the Attacks on the Kurdish People".

"We are all Kurds, we all belong to the DTP," chanted the crowd.

Some two dozens youths threw stones at riot police who responded by firing a single gas bomb, An AFP correspondent witnessed.

The renewed tensions over DTP's closure are expected to further undermine a government initiative announced in August to expand Kurdish freedoms in a bid to erode popular support for the PKK.

The reform drive already faltered last week when one person was killed in violent Kurdish protests in the southeast over claims that Ocalan's prison conditions have deteriorated.

The PKK responded by killing seven soldiers in an ambush in northern Turkey Monday.