The authorities beefed up security for the flashpoint event, which has been mired in bloodshed in the past. Several dozen people were detained for displaying support for Kurdish separatists fighting the government.

In the Mediterranean port of Mersin, home to a particularly militant community of migrant Kurds, police used water cannons and tear gas to disperse some 1,000 youths demonstrating in support of jailed Kurdish rebel leader Abdullah Ocalan.

"Without Ocalan we will bring the world down on your head," they chanted, in a reference to allegations that the leader of the Kurdistan Workers' Party (PKK) is being poisoned in prison.

At least 20 protestors were detained and several people injured, an AFP photographer said.

Newroz Day, which marks the arrival of spring and the Kurdish New Year, has become a platform for Turkey's Kurdish minority to demand greater freedoms or voice support for the PKK.

The group which has waged a bloody separatist campaign in the mainly Kurdish southeast since 1984 is listed as a terrorist group by Ankara and much of the international community.

The largest crowd -- about 100,000 people -- gathered in Diyarbakir, the main city of the southeast, where militant revellers chanted pro-PKK slogans. Police detained eight people.

Three women were slightly injured when demonstrators hurled stones at the police and the security forces fired warning shots in the air, the Anatolia news agency reported.

About 30 people were detained in other cities, it said.

In Istanbul, Turkey's biggest city, 50,000 people attended the festivities lighting traditional bonfires and dancing to Kurdish folk music.

"Real democracy or nothing," they shouted, while a group of youths unfurled a giant portrait of Ocalan before police intervened to take it down.

The festivities were organised by Turkey's main Kurdish political movement, the Democratic Society Party, whose members have in recent weeks become increasingly targeted by judicial action over charges of backing the PKK.

In Ankara, Prime Minister Recep Tayyip Erdogan appealed for peace and unity at official Newroz ceremonies, held in a bid to prevent the day from being monopolised by Kurdish militants.

"Let the seeds of hatred and hostility burn in the bonfires," Erdogan said. "As long as we do not hurt each other's feelings, no one can damage our unity."

He then lit a bonfire and several ministers jumped over it.

Newroz is also celebrated in Iran and other Muslim communities in the Caucasus and Central Asia.

Celebrations in Turkey have been relatively calm in recent years, but police in Istanbul and nearby Kocaeli last week detained 12 suspected Kurdish rebels in possession of 11.7 kilograms (25.7 pounds) of plastic explosives, reportedly intended for bomb attacks at Newroz.

The run-up to the festival was also marred by accusations by Ocalan's lawyers that the PKK leader, whom many Kurds see as a freedom fighter, is being gradually poisoned with toxic substances in the prison island of Imrali, where he is the sole inmate. Ankara has denied the claims.

In 1992, in the bloodiest Newroz so far, about 50 people were killed by the security forces during clashes across the southeast.

More recently, in 2002, two men were crushed to death during a police crackdown on violent Newroz demonstrations in Mersin.

Under pressure from the European Union, which it is seeking to join, Ankara has in recent years broadened Kurdish cultural freedoms.

But Kurdish activists say the reforms are inadequate and have called on the government for a general amnesty for PKK militants to encourage them to end their armed campaign, which has resulted in more than 37,000 deaths.