"Around 30 terrorists were neutralized [killed]" and 960 other people, most of whom were women and children, were detained, taken to the town of Diffa and handed over to the Nigerian military authorities, it said.
An elected official in Toumour, a village near the town of Bosso bordering Lake Chad, confirmed Wednesday that "a large number of Boko Haram" fleeing Sambisa had been intercepted on Niger's border "and handed over to the Nigerian authorities."
Another official said that many others, however, "are heading towards (the islands) on the lake, especially women and children, in terrible conditions."
State TV channel Tele Sahel said late Tuesday that on March 7 aerial surveillance spotted a "massive movement of people" along the Kamadougou Yoge River, which marks the border between the two countries, who were heading towards Lke Chad.
The report said they were members of the Boko Haram jihadist group, who were fleeing their hideout in Sambisa forest in northeast Nigeria after coming under pressure from their rivals, the Islamic State West Africa Province (ISWAP).
ISWAP split from Boko Haram in 2016 and rose to become the dominant group in the region's long-running jihadist turmoil.
It seized swathes of territory under Boko Haram control after leader Abubakar Shekau was killed in clashes with ISWAP in May 2021.
Seeking to prevent the group from reaching Lake Chad and using its marshlands as a haven, the army tried to negotiate a surrender, using envoys and dropping leaflets, but eventually launched a dawn assault on March 11, Tele Sahel said.
The group's violence has killed over 40,000 people and displaced around two million from their homes since 2009, according to the United Nations.
The vast Lake Chad region, shared by Nigeria, Niger, Cameroon and Chad, is a notorious bolthole for both Boko Haram and ISWAP, who set up camps on islands in its marshlands.
The four countries set up a Multinational Joint Task Force in 2015, comprising 8,500, with the aim of defeating the armed group