The vigilantes were seeking those responsible for the deaths of more than 150 people, killed by assailants dressed in black and wearing masks, similar to so-called ninjas.

According to local newspaper reports, three of the killer mob's victims were beheaded and one was burned to death. The severed heads were then paraded through village streets.

Police later arrested more than 50 people, suspected of being among the mob. The district police chief, Lieutenant Colonel Suhartono said that residents had overreacted to rumours about ninjas.

Witches and warlocks

The main targets of the ninja killers seem to have been ducans (black magic practitioners) - witches and warlocks are now receiving police protection - but some Muslim preachers and local public figures have also been targeted.

Sorcery and witchcraft still prevalent in Indonesia

Some of the victims were tied into bundles and hung from trees, whilst others were thrown into mosques. Sometimes there were power cuts just before the murders took place.

Representatives of five Indonesian religious and community groups have called on the national police chief to take urgent measures to halt the "terror campaign", Indonesian radio reported on Saturday.

Ahmad Bagja, secretary-general of the largest Islamic group in Indonesia says that Islamic preachers have received both telephone and direct threats.

So far it is unclear who is behind the campaign, but a team from the Indonesian army has been dispatched to Banyuwangi, in East Java, where many of the dead were found.

The BBC's correspondent in the region, David Willis says that sorcery and witchcraft are still prevalent in Indonesia. Even ousted President Suharto was known to hold regular consultations with a clairvoyant - meetings that are believed to have shaped many of his political decisions.