An unidentified plane bombed a funeral ceremony in a village on the Niger-Nigeria border, killing at least 36 mourners, Niger's army said Wednesday.
Tuesday's strike came amid Niger's involvement in a growing regional offensive against Nigerian Boko Haram fighters, who have waged a brutal six-year insurgency that has killed over 13,000 people. Niger, Chad and Cameroon have suffered attacks in recent weeks, amid their bid to stop the armed group.
Niger has been hit by several bombings blamed on Boko Haram.
It was not clear who dropped the bombs, but Nigeria denied responsibility.
"It's not to my knowledge, and there has not been any report from our people of such an incident," said Air Commodore Dele Alonge, a spokesman for Nigeria's air force.
A Niger army report obtained by Agence France-Presse said the plane's "origins remained undetermined."
Niger, which has committed more than 700 troops to the regional force, is part of a joint regional force that is involved in ongoing assaults against Boko Haram.
Meanwhile, Boko Haram has renewed its threat to use violence to try and disrupt Nigeria's upcoming elections, scheduled for March 28.
In a video published by the SITE Intelligence Group, Boko Haram leader Abubakar Shekau reiterated warnings that the group will use violence to disturb the elections
Shekau also claimed responsibility for an attack on Saturday on the town of Gombe in northeastern Nigeria.
The Nigerian army and two fighter jets repelled the Boko Haram attackers. As they retreated from Gombe, the Boko Haram fighters scattered papers warning residents not to vote in the elections because polling stations would be attacked.