Street battles have continued for a fourth day in the southern Nigerian town of Warri between heavily armed gangs from two rival communities.
Scores of buildings have been burnt and more than 30 people are now known to have died since the fighting began on Friday.
The Ijaw militants are said to have attacked unarmed civilians
The army is being deployed on the streets, but local residents say there are parts of the town where the clashes have continued without intervention from the security forces.
Despite assurances from the army that the clashes have been brought under control it is clear that the situation in some districts of the town remains extremely volatile.
Terrified residents have been fleeing gunfire on Monday and describe no-go areas where the security forces have not penetrated.
Speaking to the BBC by phone, with gunfire audible nearby, residents of Warri from the Itsekiri community say heavily armed Ijaw militants have been attacking unarmed civilians and burning houses.
One resident, who asked not to be named for fear of reprisals, said that more than 30 people from his community had been killed.
There have been similar reports of attacks by Itsekiris on Ijaw communities over the past few days as well.
The army is being more cautious about the number of casualties, but it is clear from numerous eyewitness accounts on both sides that the final death toll will be substantial.
These are two communities that have long held grievances over access to political and economic power in the region, and in particular it is the Ijaw who perceive the Itsekiri to have been favoured by both the government and multi-national oil companies operating in the area.
Following widespread violence between the two communities earlier this year, the oil companies evacuated most of their operational staff from the area, drastically cutting back production.
Some of that output has subsequently been restored, but these latest clashes are once again causing concern over the impact they will have on Nigeria's oil industry.