* Victims say attacks committed by their former neighbours
* Violence mixing politics and land conflicts
* Reprisals leave communities polarised
By Joe Bavier
TAI, Ivory Coast, June 21 (Reuters) - The gunmen knew exactly who they were looking for when they entered Paul Kumbiamba's village in western Ivory Coast and fired a rocket through the front door of his family's home.
"They came into the courtyards of the houses and called out names. When the people inside came out, they killed them," said the 22-year-old cocoa farmer, who with his mother escaped a June 12 raid that killed one brother and put another in hospital.
Many like Kumbiamba, who was born in Ivory Coast to parents from neighbouring Burkina Faso and is thus widely regarded as a foreigner, had been starting to feel the country's dark days of xenophobia-charged politics were behind them.
Former President Laurent Gbagbo, whose decade-long regime treated the country's immigrants as second-class citizens, was brought down in last year's civil conflict and now awaits trial at the International Criminal Court for crimes against humanity.
The militias and foreign mercenaries he used to spread terror in the cocoa-rich west fled to neighbouring Liberia by the thousands.
But a series of cross-border attacks earlier this month that killed at least 23 people, including seven United Nations peacekeepers, have highlighted the lingering threat posed by the now-exiled former regime and driven a wedge between neighbours struggling to heal the wounds of the recent past.
"It was people from our village who attacked us," Kumbiamba said. "The ones we saw were those who are now in Liberia."
POWER CHANGES HANDS ...
A decade of north-south partition and simmering political crisis in the world's top cocoa grower ended last year with a brief but brutal civil war which was sparked by Gbagbo's refusal to acknowledge defeat in 2010 polls.
Around 3,000 died before Gbagbo was captured and his forces routed by troops loyal to his presidential rival, Alassane Ouattara. While the fighting has ended, efforts under Ouattara's new government to heal the wounds in Ivorian society opened by the conflict have been faltering.
Some 200,000 refugees, many fearing reprisals at the hands of Ouattara's supporters for backing Gbagbo, fled into Liberia in the company of Gbagbo's fighters and their Liberian mercenary allies. Around 60,000 Ivorians remain there today.
"Now that the power has changed hands, those who were in control thought that they were threatened, so they left ... Lots of them left. Everyone in the party in power left," said Tere Tehe, deputy mayor of the border town of Tai.
The Ivorian government blames the new violence in the west on those same exiled fighters and alleges they are bankrolled by Gbagbo allies still at large in the region.
New York-based Human Rights Watch, in a report released just days before the June 8 attack on the peacekeepers, warned that Ivorian and Liberian fighters were behind a series of raids that had killed 40 people, most of them foreigners, since last July.
"During the fighting, we captured combattants on the ground. And during the interrogations ... they admitted the recruitment was done in the refugee camps in Liberia," said Losseni Fofana, the Ivorian army's top commander in the west.
It was not possible to independently verify his allegation; the United Nations has launched an investigation to uncover who is behind an ambush that killed the peacekeepers from Niger.
... AND BATTLE FOR LAND GOES ON
What is clear is that the underlying problem goes much deeper than the battle between two political fanctions.
Home to some of the world's richest cocoa farmland, the west has long been the centre of tensions between native ethnicities and migrant farmers from elsewhere in Ivory Coast and Mali and Burkina Faso to the north.
If Ivory Coast is now the world's top cocoa producer, it is in part because those immigrants toiled for decades in its fields and gradually acquired ownership of most of the plantations - to the growing resentment of local ethnic groups.
Gbagbo, himself an ethnic Bete from the southwest cocoa belt, used those tensions to solidify his political base and mobilise the youth militias used to intimidate the opposition. It was a policy that regularly sparked tit-for-tat killings and left the region perpetually teetering on the brink of a conflict along ethnic faultlines.
That pattern risks being repeated with immigrants accused of chasing native ethnic groups from a number of villages along the border zone in retaliation for nearly a year of increasingly brutal cross-border incursions by suspected Gbagbo loyalists.
"The foreigners started burning houses. They started killing people ... They killed my aunt, my little sister and her two children," said 34-year-old Angelique Toklaon, who fled the village of Ziriglo for the relative safety of Tai with her four children in September.
"They want to chase us away and take our land. That's the whole problem.
Ouattara has launched a "truth and reconciliation" process to get communities in the west and elsewhere to come to terms with last year's violence. The thorny issue of land ownership is due to go before parliament later this year. But all this will take time.
In the meantime, the U.N. mission is reinforcing its positions along the border and the Ivorian army has deployed hundreds of troops for what it says is an operation to "mop up" any fighters on the loose.
Witnesses said its forces used machineguns and fired mortars on Sunday across the Cavally River in an exchange of fire with gunmen on the other bank in Liberia.
For now, few expect the violence to plunge the country into a renewed conflict. However, it has dealt a major blow to hopes that the war's end might put a stop to the cycle of killing.
"The attacks appear confined to the border area at present," said Matt Wells, West Africa researcher for HRW. "But they pose a serious threat to efforts to end the country's deep communal divisions." (Editing by Mark John and Jon Hemming)