At least three people have been killed and more than 20 wounded in a bomb explosion in the southern Philippines. No one has claimed responsibility for the attack.

"The bomb exploded beside the public market of Koronadal city, inside a video game stall in that public market," informed Philippine military spokesman Lieutenant Colonel Daniel Lucero, who also said the crude bomb went off in mid-afternoon in Koronadal in South Cotabato province.

A spokesman for President Gloria Macapagal Arroyo immediately condemned the attack.

There was no immediate claim of responsibility. But it was the second bombing in Koronadal in three months. At least 10 people were killed in a bombing in May that the government blamed on the separatist Moro Islamic Liberation Front, or MILF.

Colonel Lucero said there was no immediate evidence linking the attack to the MILF.

Koronadal, a city of some 780,000 on the island of Mindanao, was gearing up for the start Friday of a week-long festival.

A market vendor named Abo said there was a loud explosion, which he immediately knew could only be a bomb.

The government has been trying to restart stalled peace negotiations with the MILF. It was not immediately clear what effect, if any, this latest attack will have on the peace process. Presidential spokesman Ignacio Bunye says the government will go after the perpetrators, but that the attack should not derail the peace talks. He says preliminary talks have made significant headway, and that the door is open for, as he put it, those who genuinely want peace on the island of Mindanao.

Peace talks, with Malaysian intermediaries, have bogged down over the issue of outstanding warrants for the arrests of MILF leaders. On Wednesday, President Arroyo told Malaysian Deputy Prime Minister Abdul Ahmad Badawi that she would not oppose legal action to lift the warrants. But she insisted that the petition to lift them must come from MILF lawyers.

Under Philippine law, only the courts can suspend the warrants.

An MILF spokesman said, however, that petitioning the court would be tantamount to recognizing the Philippine constitution, which he said is against longstanding MILF policy.

The MILF has been fighting for nearly 30 years to create a Muslim state in the southern Philippines.