An attack on a police post in the restive Indonesian province of Maluku has left six people dead, five of them policemen. The attack took place on the island of Seram in Maluku province, which has been the scene of long-running tension between Christian and Muslim communities. There is fear the killings might mark a new resurgence of violence in Maluku after a period of relative calm.

An unknown number of gunmen hit the police post in the village of Loki on Seram island before dawn. Five police and one of the attackers died in the ensuing gun battle. Investigators say they are still trying to determine the motive behind the attack.

Maluku was the scene of bitter inter-communal violence between 1999 and 2001, when some nine-thousand people are estimated to have died. There has been relative peace since a peace deal in 2001, but the Christian and Muslim communities still lead largely separate existences, and tensions between the groups still occasionally flare into violence.

But it is not clear if the latest attack was related to religious tension or had another cause. The rule of law is sometimes shaky in more remote parts of the 14,000-island Indonesian archipelago and criminal gangs, illegal loggers and even the army have been known to come into conflict with the police.

Owais Parray is the head of the U.N. Crisis Prevention and Recovery program for Maluku and a number of similarly troubled surrounding provinces. He says it is too early to determine what was behind the latest incident, and it is much too early to blame religious differences.

"There are other elements that feed into this violence, I do not think it is religiously," he said. "I mean, it has been characterized as such, but I think there are other factors that have contributed to this continued violence."

But Mr. Parray says the situation is significantly better than it was five years ago, or even last year, but that there is a pattern of violence, with relatively peaceful periods punctuated by incidents that arrive without warning.

The Indonesian police say they believe that unidentified groups trying to revive the conflict might be behind the shooting of the police, that is usually a police reference either to Islamic extremists or Christian separatists.