There was no immediate claim of responsibility for the blast, the deadliest in a string of bombings across Turkey this year, but immediate suspicions fell on separatist Kurdish rebels, who have been fighting the government since 1984.

The blast occurred at around 9 pm (1900 GMT) near a bus stop at a crowded park in Diyarbakir's impoverished Baglar district, in which tea gardens are a favorite venue to relax in the evenings.

It was heard throughout the city, shattering the windows of nearby buildings and opening small cracks in several walls.

Four of the injured remained in hospital Wednesday morning.

As one body was torn apart beyond recognition, police were considering the possibility that it belonged to the person carrying the bomb, which may have gone off prematurely.

The park may not have been the original target, they added.

Diyarbakir, a city of around one million people, is a hotbed of Kurdish separatist militancy.

"We heard that terrible bang and then we saw flames rising as high as five meters from the ground," said Hasan Ozcetinkaya, an employee of a gas station across the street.

"I was resting at home when I heard the explosion. I thought it was either an earthquake or I was losing my mind," Mehmet Sanli, a 75-year-old resident of a building next to the park, said. "I went out barefooted and the street was littered with pieces of glass."

Diyarbakir Mayor Osman Baydemir, a popular Kurdish politician, condemned the blast as a blow to efforts to restore peace in the southeast, the theatre of a bloody 22-year Kurdish rebellion that has claimed more than 37,000 lives.

"This is a provocation. This is a sabotage to peace," Baydemir said.

The rebel Kurdistan Workers' Party (PKK), blacklisted as a terrorist group by Turkey, the European Union and the United States, has notably stepped up violence this year after it called off a five-year unilateral ceasefire in June 2004.

At least 75 members of the security forces and 104 rebels have been killed in clashes and attacks since the beginning of the year, according to an AFP count.

Kurdish militants have also claimed responsibility for 16 bomb attacks across Turkey, including tourist resorts in the west, which killed a total of 12 people and left around 200 others injured.

Tuesday's attack is likely to put further strain on the government of Prime Minister Recep Tayyip Erdogan, which has come under mounting criticism for failing to stop bloodshed in the southeast.

The bomb exploded hours after the arrival in Ankara of a special US envoy, retired general Joseph W. Ralston, who was to hold talks with Turkish officials on Wednesday to discuss measures to curb the PKK.

Ankara has long urged Washington to crack down on PKK bases in neighboring northern Iraq, where the group has enjoyed safe haven for years.

On Monday, Turkey's main Kurdish party, the Democratic Society Party, urged the PKK to call a ceasefire.