Fierce fighting this weekend pitted Boko Haram fighters against another jihadist group, affiliated with the Islamic State, in the Lake Chad region, anti-jihadist militiamen said on Monday, adding that "more than 60 people are feared dead".
The fighting took place on Friday and Saturday when Islamic State in West Africa (ISWAP) fighters ambushed a fleet of Boko Haram boats on the islet of Kaduna Ruwa in Lake Chad, which straddles Nigeria, Niger, Cameroon and Chad, the sources said.
"The fighting began at around 4pm (1500 GMT) and continued until Saturday morning. Nine Boko Haram boats and all the fighters on them were sunk," Ibrahim Liman, a leader of an anti-jihadist militia in the region, told AFP.
In addition to the fighters, several dozen hostages kidnapped two weeks earlier were present on these boats. "At least 60 people died, at the very least, if you count the fighters and their dozens of hostages", said Mr Liman.
"We don't have a definitive assessment of the fighting, but there will certainly be more than 60 dead. Nine boats sank, and (...) we know that the rebels charge them a lot when they are on operations", added another anti-jihadist militia leader, Kabiru Habu.
However, no bodies have yet been found, according to local sources, and no confirmation of this death toll was available from the local authorities on Monday.
- Kidnappings -
Two weeks earlier, Boko Haram fighters had left their camp in the Diffa region of Niger for the island of Doron Baga on the Nigerian shore of Lake Chad, terrorising the local population by looting and kidnapping, Sallau Arzika, a fisherman from the village of Baga, told AFP.
They kidnapped several dozen people, including fishermen and at least eight Fulani women, according to Mr Arzika and Labo Sani, also a fisherman.
The jihadists beheaded one of the fishermen and gave his head to other fishermen to take to a military contingent in Cameroon to threaten them with an attack, according to these sources.
They were intercepted by ISWAP troops, who then hunted down their rivals and attacked the Boko Haram fighters and their hostages.
In February and March, the two factions of Boko Haram and ISWAP clashed for control of the islands in Lake Chad.
According to fishermen and local anti-jihadist militiamen, both factions lost many men in the fighting. The jihadist conflict has killed more than 40,000 people in north-east Nigeria and displaced more than 2 million since 2009.