Fierce fighting broke out with the soldiers, which included the Cameroonian army and troops from the Multinational Joint Task Force, a five-nation anti-jihadist mission.
The assailants succeeded in raising their black flag before being repelled.
Around 40 assailants were captured, another security source said.
"More bodies have been recovered from the water," a source said.
Most of the military fatalities were sailors who had been sent to the Lake Chad region as part of the fight against Boko Haram, he said.
Boko Haram has led a decade-long uprising to establish a hardline Islamic state in Nigeria's northeast, killing more than 27,000 people and leaving 1.8 million homeless.
The insurgency has spilled into the Lake Chad region, the crossroads between Nigeria, Niger, Chad and Cameroon, inflicting heavy loss of life, mass displacement and economic damage.
The multinational task force, headquartered in the Chadian capital Ndjamena, pools troops from Benin, Cameroon, Chad, Niger and Nigeria.
Cameroon's armed forces are also grappling with an armed revolt by separatists in two English-speaking regions in the west of the country.
According to the International Crisis Group think tank, 1,850 people have been killed in the domestic insurgency, while more than 530,000 people have been forced from their homes, according to UN figures.
(This story has not been edited by Business Standard staff and is auto-generated from a syndicated feed.)
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