Turkey's military on Wednesday imposed a curfew in parts of the southeast after at least 21 people were killed in pro-Kurdish protests over the government's failure to act against jihadists attacking the Syrian border city of Kobane.
The disturbances were the worst outbreak of such pro-Kurdish violence in years and risked derailing Turkey's own fragile peace process with the Kurds.
In a move unprecedented since the deadliest days of the Kurdish insurgency in the 1990s, the army was deployed to impose a curfew in several cities in the east.
The violence was concentrated in the mainly Kurdish southeast but also flared in Istanbul, Ankara and other cities, with empty buses firebombed and protesters hurling stones at police.
In capital Ankara, security forces used tear gas and water cannon to disperse hundreds of protesters.
Prime Minister Ahmet Davutoglu blamed "hooligans" for the unrest that threatens to hurt a fragile peace process between Ankara and Kurdish rebels.
"I urge my fellow citizens... not to let themselves be exploited by marginal groups and I reiterate that public order will be restored by any means," he said after a meeting with ministers and security chiefs.
The ruling Justice and Development Party (AKP) government has so far not intervened militarily against Islamic State (IS) jihadists trying to take Kobane, to the fury of Turkey's Kurds.
Ten of the deaths came in Turkey's main Kurdish city of Diyarbakir, where the most intense rioting took place overnight Wednesday, the government said.
Five of the deaths were blamed on clashes between Kurdish activists and supporters of the HUDA-PAR Kurdish Sunni Islamist group which is sympathetic to IS.
"Everyone should refrain from expressing their hatred and displaying violence so that the protests do not spread," Agriculture Minister Mehdi Eker said on a visit to Diyarbakir, blaming the clashes on the "lobby of chaos".
The clashes caused extensive damage in the city with shop fronts burned out and buses set on fire.
Other people were reported killed in Mardin, Siirt, Batman, Mus and Van -- all cities in the southeast of Turkey with large populations of Kurds.
The Turkish army has been deployed on the streets in parts of six cities to enforce an open-ended curfew.
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In Diyarbakir, Turkish troops and tanks were patrolling the city of 1.5 million people and the usually thronged streets were deserted, an AFP correspondent reported.
Schools were closed in Diyarbakir until Monday and all flights into the city were cancelled.
- 'Peace under threat' -
The world's largest stateless people, Kurds are spread across Turkey, Iraq, Iran and Syria. Kurdish militants have waged a deadly insurgency for three decades for self-rule in Turkey.
However, a peace process with the Turkish government appeared to be making progress until the Kobane standoff.
Police also used tear gas and water cannon to disperse angry pro-Kurdish protests in Istanbul on Tuesday night. Some 98 demonstrators were arrested and dozens injured, Turkish television reported.
The violence even spread outside Turkey's borders, with street clashes between hundreds of Kurdish and Islamist supporters in Germany's northern port city of Hamburg leaving 23 people wounded overnight.
In one act that enraged secular Turks, Kurdish demonstrators in Mardin set fire to a statue of the secular founder of modern Turkey, Mustafa Kemal Ataturk.
The outlawed Kurdistan Workers Party (PKK), which battled Turkish forces since 1984 in an insurgency that has claimed 40,000 lives, has largely observed a ceasefire since March last year.
But jailed PKK leader Abdullah Ocalan said in a message relayed by his brother from his prison on the island of Imrali on the Sea of Marmara that the government had until mid-October to show it was serious about the peace process.
"Peace under threat," headlined the Hurriyet daily above an apocalyptic picture of vehicles on fire in the protests.
Kurds, who make up from 15 to 20 percent of Turkey's population and are its largest minority, have been particularly irked by the reluctance of the authorities to allow Turkish Kurds to cross the border to fight Islamic State jihadists.
The government has parliamentary authorisation to use the military in Syria but says it will only send in troops if there is a coordinated international effort to oust President Bashar al-Assad.