Cue – Indonesia's reputation for political stability under the firm hand of President Suharto has been shaken recently by a series of riots in which at least eleven people have died and hundreds of buildings destroyed.

There've been specific, local factors behind each incident, but they've all involved attacks by one ethnic or religious group on another. Many Indonesians now fear that their government's authoritarian approach to maintaining unity among the country's disparate people is no longer effective.

One of the areas most affected by ethnic conflict is near Pontianak, a city on the west coast of the island of Borneo, where indigenous tribes live together with settlers from other parts of Indonesia. Our Jakarta correspondent Jonathan Head has just been to the area:

The road that goes north along the coast from Pontianak presents a striking vignette of Indonesia's extraordinary ethnic diversity. Many of the inhabitants of this low, swampy region sitting astride the equator are Muslim Malays whose elegant wooden houses sit above the creeks that cut inland from the sea.

Here and there the bright red and gold paintwork of a Chinese temple flashes through the coconut plantations - the Chinese are more visible here than anywhere else in Indonesia. People have come from all over the archipelago - the seafaring Bugis who arrived in their teak-hulled schooners, and the dark-skinned farmers from the barren island of Madura. They've all been drawn to Borneo by its rich natural wealth, either its gold, its timber, or just more land for growing rice.

But move just a few kilometres inland, and everything changes. We had decided to travel out of Pontianak to investigate sketchy reports of a violent conflict between the Madurese settlers and indigenous Dayaks, the original head-hunters of the Borneo rainforest. Much of the rainforest has long been cut down, but the Dayaks continue to live as subsistence farmers, alongside the incomers.

Occasional clashes have occured in the past, but these are the worst anyone in the area can remember. Hundreds of houses are said to have been destroyed, and at least two people killed. Everone we spoke to believed that the number of dead was much higher.

The problem was that the Indonesian authorities have decided to impose what amounts to a news blackout. No-one is being allowed into or out of the worst-affected areas, and no information is being given out. The official reason for the roadblocks is to prevent large groups of Dayaks reaching the city to carry out revenge attacks, but it also means there are no reliable reports of what's happening.

Local journalists told us the military hospital was believed to be full of casualties from the fighting, but they were being denied access. When we tried to visit a refugee camp, soldiers barred our way. A heavy machine gun was propped up on the desk of the guard post ready for any further trouble.

It wasn't hard to see where the real trouble began. About fifty kilometres north of the city, the roads were suddenly deserted, and houses boarded up.

Without any warning, we had stumbled into what looked like a war zone. Soldiers were everywhere, walking alongside the ricefields or driving east in trucks or on motorbikes. They stared at our car, but made no attempt to stop us. They were all carrying automatic weapons, and all wore the uniform of Indonesia's elite combat regiment, which has been drafted in from other areas of the country to help deal with the fighting. On the walls of their homes people had painted their ethnic identities - Malay, Javanese, anything that might deter an attack by gangs from the two rival ethnic groups.

The few people who were visible were extremely tense - one Dayak shop-owner told us that soldiers had opened fire on a group of Dayaks right outside his house. It wasn't long after that that we were pulled over by a military patrol and taken into their headquarters for questioning.

Officially, there should have been no restrictions on travelling there, but as elsewhere in Indonesia, it is the army that decides where journalists can and cannot go. When the local commander politely explained that we would have to leave, there was no point in arguing. His assurance that there was nothing to see, that the area was calm, rang hollow given the level of military activity and the obvious nervousness of his troops, but there was little else we could do but go, grateful that he hadn't detained us any longer. One local journalist is still in custody over his reporting.

Indonesians are fond of acronyms, and one commonly used when trying to explain to foreign journalists why certain subjects are taboo is SARA. I'm sorry, a police officer or soldier will say as he puts his hand over your camera, that's a SARA issue. SARA stands for ethnicity, religion, race, and class, areas journalists are supposed to avoid for fear of damaging national unity. That may help explain why what appears to be a serious ethnic conflict has gone almost unreported in the Indonesian media. But some Dayaks say there's another reason. They believe the army itself has killed large numbers of people, killings it now wants to cover up. It's impossible to know how much truth there is in these allegations, but they are widely believed. That makes the task the military has given itself, as a neutral party ready to douse the flames of ethnic hatred, an almost impossible one to carry out.