By Tomi Soetjipto and Jerry Norton

JAKARTA, Jan 11 (Reuters) - A bomb blast killed four people late on Saturday at a cafe on Indonesia's Sulawesi island and wounded at least three others, police and hospital sources said.

It was not immediately clear who was responsible for the attack, the latest in a number of bombings to hit Indonesia, the world's most populous Muslim nation, in recent years.

In October 2002, bombs on Indonesia's premier tourist island of Bali killed 202 people, mostly foreign visitors, in what was the deadliest such incident since the September 11 attacks on the United States.

Saturday's bomb went off at a karaoke cafe at around 11 p.m. (1500 GMT) in South Sulawesi province's Palopo area, police said.

Asked whether a bomb had exploded, a police official in Palopo, who declined to be named, told Reuters by phone early on Sunday: "Yes, that's true."

He said the blast site was on the road to South Sulawesi's capital Makassar, which lies 1,400 km (875 miles) east of Jakarta.

Another police official, Muhammad Nursi, told Reuters: "The forensics team from Makassar is still on the scene. So far there is no lead." He had no details on the type of bomb used.

A nurse at a Palopo hospital said the three who were wounded had been brought there and then released after treatment for minor injuries. She said the victims were local.

The 2002 Bali bombings were blamed on Southeast Asia's militant Islamic Jemaah Islamiah network, linked to Osama bin Laden's al Qaeda.

Jemaah Islamiah was also tied to a December 2002 bombing at a McDonald's restaurant in Makassar, which killed three.

There have been sporadic clashes in parts of Sulawesi between Christians and Muslims in recent years, with victims estimated to number in the thousands.

Indonesia has arrested scores of suspects with militant Islamic links over the Bali and Makassar cases, as well as an August 2003 bombing of a luxury Jakarta hotel which killed 12.

However, violence and bombings in Indonesia's sprawling archipelago can stem from causes other than religious extremism, with politics, ethnic differences, and the settling of scores by criminals among the motives cited.

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