Three suicide bombers killed at least nine people in separate attacks in the southeastern Niger city of Diffa near the border with Nigeria, shattering several months of calm in the troubled region.
The attacks occurred late Monday in the city, a regional capital that is a frequent target of the Boko Haram jihadist group, a local official who requested anonymity told AFP.
He said "two young women and a man" blew themselves up at three different sites including an Islamic school.
"For the moment there are nine dead, as well as wounded," he said.
Ibrahim Amadou, a resident, said the three detonations were "almost simultaneous" in Koura, an old district of the city, with one near the Koranic school, one near a mosque and the third by a shop.
People are afraid, "but they aren't giving in to panic," Amadou said.
According to accounts on social media, three explosions were heard at around 10 pm (2100 GMT) Monday.
Another resident, Ari Maman, said he and others were surprised the attacks happened in the heavily secured city of around 600,000. "We expect attacks across the region, except in the heart of the city," he told AFP.
Security forces have cordoned off the sites and were carrying out search operations throughout the city, a security source said.
The attacks came as Niger President Mahamadou Issoufou arrived in Paris for an official visit Monday. He was to continue to Brussels Tuesday.
They also follow several months of calm in the Diffa region which since February 2015 has suffered numerous attacks by Boko Haram based across the border in northeast Nigeria.
In late April, Niamey announced a military operation against Boko Haram in the region of Lake Chad, which links Niger, Chad, Nigeria and Cameroon.
The group, which is seeking an Islamic state based on Sharia law, has caused the deaths of at least 20,000 people since it took up arms in 2009 in Nigeria.
Some 2.4 million people have been displaced in northern Nigeria, Cameroon, Chad and Niger, according to the UN refugee agency UNHCR.
Niamey hopes to allow thousands of people to return to the islets of Lake Chad which Boko Haram uses as rear bases for attacks.
In late January, UNHCR launched an appeal for $156 million (127 million euros) to help people displaced by the Boko Haram campaign of violence.
The conflict in the Diffa region has caused delays in the construction of a pipeline for exporting Niger's crude oil to Cameroon via Chad. Niamey recently said work would begin late this year.
In addition to Boko Haram attacks in the southeast, Niger faces repeated attacks by other Islamist groups in the north and west.