Gunmen attacked a high-security prison in Niger early on Monday in an apparent bid to free Islamist militants from Al Qaeda and Boko Haram.
But the assault was repulsed and no inmates escaped, authorities said.
The prison is located at Koutoukale, 50 km (30 miles) northwest of the capital Niamey.
Most inmates were suspected members of Boko Haram, which has waged an insurgency based in northeastern Nigeria. A small number were suspected of belonging to al Qaeda in the Islamic Maghreb and other militant groups, the official said.
Boko Haram has carried out raids into Niger from its bases across the border in northeastern Nigeria.
“I can confirm one dead among the attackers. He was wearing a suicide vest,” Interior Minister Mohamed Bazoum told Reuters by telephone. “The situation is now under control and our forces are combing the area to try to catch the attackers still at large,” he said. A ministry spokesman said no prisoners escaped.
Bazoum said the most likely culprits were the Mali-based Movement for Unity and Jihad in West Africa (MUJWA), one of a number of armed groups operating in the widely unpoliced Sahara.
Niger is surrounded by unstable states, most of them struggling with Islamist insurgencies. Militants have also crossed from Mali to its west and Libya’s conflict to its north threatens the whole region.
“We heard sustained gunfire coming from the prison just as we were going for (early morning) prayers,” the director of the Koutoukale school, Abdoul Razak Ali, said by telephone.
The attack came days after gunmen raided the house of a United States aid worker in central Niger, killed his guards and drove him across the desert towards Mali.
Gunmen also attacked a refugee camp earlier this month in Niger’s western Tahoua region bordering Mali, killing 22 soldiers.
An Amnesty International official who visited the prison in June said it held around 550 inmates, more than double the prison’s capacity, and the overwhelmed court system had too few judges to bring them to justice properly.