The "heavily armed" soldiers will "search everywhere for Boko Haram," added the source. The UN says some 50,000 people have fled Bosso after the attacks in Niger's troubled southeast.
The attacks began Friday against a military post in Bosso in Niger's Diffa region, killing 26 soldiers including two from neighbouring Nigeria.
A total of 55 insurgents from the Nigeria-based Islamist group were killed and "many" injured, according to authorities.