Jos, march 10 (AFP) -- Fresh gunfire has sent Christian villagers in Nigeria fleeing as a senior official accused the country's military chiefs of having ignored warnings about last weekend's massacre.

Residents of a mainly Christian settlement near the central city of Jos fled to a nearby police barracks for shelter at the sound of gunfire, said locals.

"We heard gunshots reverberating all over the neighbourhood and I could not wait to know who was firing the shots," Josephine Emmanuel, of Bukka Uku, about four kilometres (three miles) south of Jos, told AFP by phone.

"All people in the neighborhood have fled," she added.

Just hours earlier, members of the Fulani clan and Berom ethnic activists had clashed nearby, a senior police officer told AFP.

"Some Fulani pastoralists attempted to attack a village and Beroms repelled them," said the officer speaking on condition of anonymity.

Earlier Tuesday, Jonah Jang, governor of central Plateau state, said Sunday's carnage, which claimed hundreds of lives of mainly Christian villagers, could have been avoided had there not been security lapses.

He had alerted Nigeria's army commander about reports of movement around the area and had been told that troops would be heading there, Jang told reporters in the capital Abuja.

"Three hours or so later, I was woken by a call that they (armed gangs) have started burning the village and people were being hacked to death.

"I tried to locate the commanders, (but) I couldn’t get any of them on the telephone."

Near the central city of Jos, mass burials have been held for some of the hundreds of victims of the three-hour orgy of violence, as survivors nursed their wounds in hospitals.

Troops meanwhile patrolled the three villages where members of the mainly Muslim Fulani ethnic group embarked on their killing spree. But residents of neighbouring villages said they had already received new threats.

Officials have said more than 500 people from the mainly Christian Berom ethnic group were hacked to death with machetes, axes and daggers in three villages of Dogo Nahawa, Ratsat and Zot on Sunday morning.

In a surgical ward of Jos hospital, women nursing deep scalp wounds mourned the loss of their children.

Chindum Yakubu, 30, mother of four, described the screams of her 18-month-old daughter who was hacked to death as the family tried to flee the pre-dawn attacks.

"They removed the baby (from her back) and killed her with machete," Yakubu said.

Thousands have been killed in recent years from strife in and around Jos, which is on the dividing line between the mainly Muslim north and Christian dominated south.

"One moment it's relaxed, then the next moment people are running for their dear life," said hospital administrator Ruth Mutfwang, summing up life in the restive region.

As a group of men huddled in small groups at Dogo Nahawa, one was overheard saying "we will take revenge."

International observers have called on the government to tackle the root causes of the ethnic tensions, which have seen thousands killed here in recent years.

The UN's human rights chief Navi Pillay said, "what is most needed is a concerted effort to tackle the underlying causes of the repeated outbreaks of ethnic and religious violence... namely discrimination, poverty and disputes over land."

Nigeria's senate described the attacks as acts of "terrorism" and crimes against humanity.

But the main opposition Action Congress accused the federal government of "hypocrisy," saying perpetrators of the region's violence in recent years had not been brought to justice.

Archbishop John Olorunfemi Onaiyekan of Abuja, meanwhile objected to suggestions that this was a conflict between Christians and Muslims.

"This is a classic conflict between herdsmen and farmers, only the Fulani are all Muslims and the Berom all Christians," he told Vatican Radio.

"The international media are quickly led to report that it is Christians and Muslims who are killing one another; but this is not true, because the killings are not caused by religion but by social, economic, tribal and cultural issues."

Sunday's attacks were only the latest between rival ethnic and religious groups.

Locals said they resulted from a feud first ignited by cattle theft that was fuelled by deadly reprisals