By Ulf Laessing
NIMBO, Nigeria (Reuters) - Muslim herdsmen fleeing Boko Haram jihadists and fast-spreading desertification in the north of Nigeria are clashing with Christian farmers in the south, adding a dangerous new dimension to the sectarian tensions and militancy plaguing the country.
Thousands of people from Muslim Fulani tribes have moved southwards this year, leading to a series of clashes over land that have killed more than 350 people, most of them Christian crop farmers, according to residents and rights activists.
The fighting threatens to fracture the country further by bolstering support for a Christian secessionist movement in the southeast, which has been lingering for decades but gained fresh momentum late last year when resentment over poverty and the arrest of one of its leaders spilled over into street protests.
The conflict is also exposing a growing problem that has attracted less international attention than Boko Haram and the militants threatening oil production in the Niger Delta region.
Fertile land is becoming scarcer across Africa's most populous nation, and conflict over this dwindling resource is likely to intensify. The population of poverty-stricken Nigeria is expected to more than double to almost 400 million by 2050, according to the United Nations.
There are no signs that the secessionists will take up arms against the government like in the 1967-70 civil war that killed one million people. But the clashes and growing resentment at the arrival of Muslim herdsmen come at a time when many people in the southeast are complaining about widespread poverty.
In one of the deadliest clashes, about 50 people were killed in April when Fulanis attacked the village of Nimbo in the southeastern state of Biafra, according to residents, rights groups and lawmakers who visited Nimbo after the violence.
They said the attackers opened fire on villagers and torched a house where a priest and his family were sleeping, with the family only surviving by jumping out of a window.
"The Fulanis ... came in the town and shot at any man they saw and killed him," said Joseph Obeta, another priest in Nimbo, which is now almost deserted after hundreds of villagers fled during or after the attack.
Obeta said if there was an independent state in the southeast of Nigeria, it would be easier to prevent such violence.
"It would make a difference if the southeast were on its own."
He was echoing the sentiment of campaigners lobbying for an independent Biafra. They say they want to stop the Muslim north from dominating the Christian south of the West African country, which is split fairly evenly between Muslims and Christians.
They say the influx of herdsmen from the north is part of a plan by the government of President Muhammadu Buhari, a Fulani Muslim, to turn Nigeria into an Islamic nation - an allegation vehemently denied by the government and Buhari.
CRISES
Fulani leaders say their communities have no choice but to migrate southwards.
The precise numbers involved are unclear, but thousands first moved to central Nigeria to seek new pastures and escape the violence and insecurity of the Boko Haram insurgency.
Growing desertification - where fertile land turns into desert for reasons including over-exploitation and drought - has forced many further south this year, to more than 1,000 km from their homeland.
The Fulani leaders say they are clamping down on members who commit crimes but added that they often were themselves victims of kidnapping, attacks or cattle rustling at the hands of residents of southern farming communities.
"When they suffer maltreatment (in southern areas they migrate to), they do not usually speak up or report to police until when it becomes unbearable, then they will react," said Alhaji Gidado, head of the Fulani cattle breeder association in the southeast.
Buhari said last week that he had ordered security forces to "deal decisively" with violence between herdsmen and farmers.
But he faces a host of other crises.
His security forces are battling the Boko Haram in the northeast - the president's priority since taking office last year after making an election promise to defeat the jihadists.
Seven years into Boko Haram's insurgency that spread from Nigeria into Chad, Niger and Cameroon, regional armies have retaken most of the territory that had been seized by the group, though it still stages suicide bombings.
The countries are in a final push to defeat the hardline Sunni Muslim group, which has pledged allegiance to Islamic State, but lingering divisions in their joint task force are complicating that mission.
Buhari has also promised to crush militants that have carried out pipeline bombings in the southern Delta region and are threatening to trigger a wider conflict that could cripple oil production in a country facing a growing economic crisis.
On the problems created by Fulanis migrating south, residents and rights activists said Buhari's previous pledges to tackle the clashes between the herdsmen and crop farmers had not been backed up by any significant security action.
Human rights lawyer Emmanuel Ogebe, invited by the U.S. House of Representatives to give testimony in May about Boko Haram and other crises facing Nigeria, said the Fulanis had been operating in "plain sight" to stage attacks that were more brutal than the jihadist group.
VIGILANTES
Police have said they had increased patrols in farming areas that have been affected by violence but local youth have nevertheless taken up arms against Fulanis since the Nimbo attack.
"The Fulani people have been robbing, raping women," said 28-year old Anthony Okafor, searching cars at a vigilante checkpoint outside Nimbo. "That's why we are here."
Some residents said the youth, with their outdated rifles borrowed from farmers, would be no match for the Fulanis, who they said had assault weapons.
Officials worry poverty levels are rising in rural areas, where there are few job opportunities outside agriculture, as many scared farmers have abandoned their fields.
Stanley Okeke, head of the government council in Agwu, said production of cassava, a staple crop, had fallen significantly in parts of Enugu state, to which Nimbo and Agwu belong.
James Onyimba, leader of a community comprising six villages in Enugu, said many farmers were now sitting idle at home. "Farming is our main job. We don't have any factories," he added. "The problem of unemployment is getting worse."
(Thois version of the story clarifies reference to southeastern area)