By Joe Bavier
ABIDJAN (Reuters) - Authorities in Ivory Coast on Saturday arrested a militia leader accused of participating in one of the worst massacres committed during the West African nation's post-election violence in 2011, a military official and witness said.
Some 3,000 people were killed in the brief armed conflict that broke out after incumbent president Laurent Gbagbo refused to acknowledge defeat at the hands of his rival Alassane Ouattara in a run-off poll in late 2010.
Amade Oueremi's militia backed Ouattara during the fighting, but rights groups say his fighters participated in the executions of hundreds of suspected Gbagbo supporters in the western town of Duekoue in March 2011.
"We have arrested him. He is now in custody. We'll bring him to Abidjan where he will answer for his acts," said one army officer involved in Oueremi's arrest, asking not to be named.
He declined to say whether the arrest was linked to the Duekoue killings.
A civilian witness told Reuters he had seen the militia chief at an army base in Duekoue where he was being held on Saturday, adding that soldiers had told him that Oueremi had surrendered.
Gbagbo is currently awaiting trial before the International Criminal Court (ICC), accused of crimes against humanity, while the former first lady, Simone Gbagbo, is being sought by the court on similar charges.
More than 100 of the former president's supporters were arrested after the violence and remain in detention in Ivory Coast.
The conflict ended after Gbagbo was arrested in April 2011, allowing Ouattara to consolidate power as president. But none of Ouattara's own U.N.- and French-backed fighters have yet been arrested, despite evidence that they too committed atrocities.
Oueremi's continued liberty in spite of the accusations against him had been held up by human rights groups as an example of the government's failure to deliver impartial justice.
"Will Ivorian justice and the ICC finally balance their actions?" said Rinaldo Depagne, Ivory Coast researcher for the International Crisis Group, reacting to the arrest.
"This is proof that, if they want, the state has the ability to make its authority respected, and they should do it more," he said.
(Editing by Mark Trevelyan)