|A Niger soldier patrols in Malam Fatori, in northeastern Nigeria, which was retaken from Islamist Boko Haram militants by troops from neighbouring Chad and Niger, on April 3, 2015 (AFP Photo/Philippe Desmazes)|
"At dawn on April 25, fighters from the terrorist group Boko Haram riding motorised canoes attacked the island of Karamga, a position northwest of of the town of Bosso held by our defence and security forces," the ministry of defence said.
"Operations are ongoing with the support of partners to counter the ambitions of this terrorist group," the ministry added in a statement broadcast on television.
The ministry did not indicate if there were any casualties as a result of the raid.
An official from Diffa, the capital of the southeast, however warned the death toll was "very heavy in the ranks of the Nigerien army," without providing further details.
State television reported that Niger's President Mahamadou Issoufou had called a meeting of the national security council after the Islamists' attack.