Erdogan told journalists that Tuesday's attack, in which 10 people died, did not appear to have been carried out by the nationalist group that has claimed responsibility.

Asked whether Kurdistan Workers' Party (PKK) separatists were responsible, the prime minister replied: "At the moment it would seem that yes, the investigations point to them."

A shadowy nationalist Turkish group, the Turkish Revenge Brigade, had claimed responsibility for the blast, vowing on its website to avenge the killings of Turks by the PKK, which has stepped up violence this year.

Earlier Friday a senior minister was quoted as saying "hardliners within the PKK" were responsible for the attack on Tuesday evening at a crowded park in Diyarbakir.

And police also pointed the finger of suspicion at the PKK, which has fought for Kurdish self-rule in the southeast since 1984 and is blacklisted as a terrorist group by Ankara, the European Union and the United States.

"All evidence we have obtained, all analyses by bomb experts... show that the incident is very similar to other attacks the separatist terrorist group has carried out in the region and point at them as the perpetrators," police spokesman Ismail Caliskan told a news conference in Ankara.

He explained that the same type of explosives and the walkie-talkie used in the bomb had been used in at least three PKK attacks on the security forces in the Diyarbakir region earlier this year.

Caliskan said the probe into the details of the attack was continuing.

The blast killed 10 people, most of them children, and left 14 others injured, adding to tensions in the southeast at a time when stability is crucial for Turkey's bid to join the European Union.

It came a day after Turkey's main Kurdish party, the Democratic Society Party (DTP), appealed to the PKK to call a ceasefire.

Officials have said the bomb -- a homemade remote-control device planted in a flask -- went off while it was being carried to another location, suggesting that the park was not the intended target.

Even though the authorities have played down the claim as an attempt for publicity, Kurdish protesters staged violent demonstrations in Diyarbakir Thursday, accusing the government of covering up the identities of those responsible.

Separately, eight people died in clashes between Kurdish separatists and pro-government militia members in eastern Turkey on Friday.

The dead included six PKK rebels, one soldier and one militia member in a rural area close to Ercis about 100 kilometres (60 miles) from the Iranian border, a security official said.

Army reinforcements have been sent to the area.

The PKK has increased attacks on the security forces this year after it called off a five-year unilateral ceasefire in June 2004.

Kurdish militants have also claimed 16 bombings across Turkey, including attacks in tourist resorts in the west, which killed a total of 12 people and injured about 200, according to an AFP count.

More than 37,000 people have died since the start of the PKK's armed campaign in 1984.